How to Sign, Fill Out and Annotate a PDF Online

To sign, fill out or annotate a PDF online, open the PDF editor, upload the file, use Add Signature, Add Text or the highlighter, and download the result. No Acrobat, nothing to install.

Each section below is a self-contained tutorial for one task — signing, filling a form, annotating for review, adding text, inserting a logo — so jump to the one you need. For a general overview of changing a PDF, see how to edit a PDF online.

How to Add Text to a PDF

Adding text is the most common PDF edit. You might need to fill in a missing date, add a reference number, write a note in the margin, or place your name on a document.

The text goes on top of the existing content — the original layout stays untouched.

1. Open the PDF editor and upload your file.
2. Select Add Text in the toolbar.
3. Click on the page where the text should appear. A text box opens at that position.
4. Type your content. Use short, clear text — the box does not reflow surrounding content.
5. Match the size and weight. There's no font picker, so check the size of the surrounding text and set the same size, plus bold or italic if needed, so your addition blends in.
6. Match the color. Most documents use pure black (#000000) or dark gray. If you are unsure, black is the safe default.
7. Drag the text box to fine-tune its position. Zoom in if you need pixel-level precision.
8. Click Apply & Download.

Tip: If you need to add the same text to multiple pages (a header, a page number, a confidentiality notice), add a text box on each page with the same size and color. This keeps the text consistent across the entire document.

How to Sign a PDF Online

Signing a PDF replaces the print-sign-scan routine. A drawn or pasted signature is fine for many everyday documents — an internal approval, a delivery note, a rental form. If a contract calls for a certified electronic signature, use a dedicated e-signature service instead.

1. Open the PDF editor and upload the document.
2. Navigate to the page with the signature line.
3. Click Add Signature and choose a tab:
   • Draw — sign with a mouse, stylus or your finger on a touchscreen. A stylus gives the most natural result.
   • Upload — use a scanned signature saved as a PNG with a transparent background, so there's no white rectangle behind it.
4. Drag the signature onto the line and resize it — oversized signatures look odd.
5. If the document needs a date next to the signature, add a text box with the date.
6. Click Apply & Download to get the signed PDF.

Best practice: Save your signature image once and reuse it across documents. A PNG file at around 400 x 150 pixels with a transparent background works well for most signature fields. Create it by signing on white paper, scanning or photographing it, and removing the background in any image editor.

How to Fill Out a PDF Form

PDF forms come in two types: interactive forms with clickable fields, and flat forms that look like forms but are essentially static pages. The approach differs slightly for each.

Interactive forms (fillable fields)

Some PDFs have built-in text fields, checkboxes and dropdowns, and the editor tells you when it finds them. Click a field on the page and type, tick the boxes, pick dropdown values and download: the answers are saved in the fields, so the form stays fillable. Tick Flatten the form before you download when the answers shouldn't change — they become part of the page.

Flat forms (no fillable fields)

Many forms — especially older government, medical, and legal documents — lack interactive fields. They have blank lines and boxes, but clicking them does nothing. Here is how to fill them:

1. Open the PDF editor and upload the form.
2. Select Add Text.
3. Click on the first blank field. A text box appears.
4. Match the font size to the form. Most printed forms use 10pt or 11pt text. Start with 10pt and adjust — the text should fit within the field boundaries without overlapping the labels.
5. Type your response. Move to the next field and repeat.
6. For checkboxes on flat forms, place a small text box over the checkbox and type an "X" or a checkmark character.
7. Review the entire form at 100% zoom to verify alignment before downloading.

Tip: If the form has many fields of the same type (name, address, date), fill one field first, then use the same size and color for the others. Consistent formatting across all fields makes the result look professionally filled.

How to Annotate a PDF for Review

Annotations are the feedback layer of a review: highlights, comments and marks that tell the author what to change. Keep in mind that this editor writes every mark into the page itself — the author can't switch them off like comments in Acrobat — so always send a marked-up copy and keep the clean original.

1. Upload the PDF to the editor.
2. Highlight key passages. Open the drawing tools, pick the highlighter, choose a color (yellow is the convention for general emphasis, red for critical issues), and draw over the text. Each highlighted section should correspond to one specific point of feedback.
3. Add comments. Use text boxes near the highlighted sections to explain what needs to change and why. Be specific: "This paragraph contradicts section 3" is more useful than "Review this."
4. Mark deletions. Draw a line through text that should be removed with the pencil tool. The original text remains visible underneath, so the author can see what you want deleted and make the final call.
5. Draw attention with the pencil. Draw an arrow to connect a comment to a specific element, outline sections that need rework, or circle a single word or number that needs correction.
6. Download the annotated PDF and share it with the author.

Review workflow tip: Use a consistent color scheme across your team. For example, yellow highlights for suggestions, red for mandatory changes, green for approved sections. This lets the author prioritize without reading every comment.

How to Add Images and Logos to a PDF

Inserting images into a PDF covers several common needs: adding a company logo to an invoice, placing a photo into an ID application, stamping a document as approved or confidential, or adding visual evidence to a report.

1. Open the PDF editor and upload the document.
2. Pick the right file format first:
   • PNG — best for logos and stamps; transparency means no white box around them
   • JPG — fine for photos, but no transparency
   • SVG — convert it with SVG to PNG first; the editor places raster images
3. Click Insert Image and choose the file.
4. Drag the image where it belongs and resize it by the corners, keeping the proportions by eye so it doesn't look stretched. Logos usually sit top-right or centred in the header.
5. Click Apply & Download.

For approval stamps: Create a stamp image (e.g., "APPROVED" with a date in a red border) as a PNG with a transparent background. Save it once and reuse it across documents. This is faster than recreating the stamp with text and shapes each time.

When to Convert to Word Instead

A PDF editor adds content on top of the existing layout. The Edit Text tool can replace a word or a line in place, but it cannot rewrite paragraphs, change fonts of existing text, restructure sections, or reflow content. If your task requires any of these operations, editing the PDF directly will lead to frustration.

Use the PDF editor when you need to add something: a signature, a form entry, an annotation, a logo, a date, a short note. The original layout stays intact, and the edit takes seconds.

Use the PDF to Word converter when you need to change something: rewrite a paragraph, update a table, change margins, swap fonts, or reorganize sections. The converter extracts the content into an editable DOCX file where you have full word-processor control. After editing in Word, save back to PDF if you need the portable format.

A practical rule: if the edit takes more than two text boxes, you probably need Word.

One signature and a date? PDF editor. Rewriting the introduction? Word.

What a PDF Editor Cannot Do

Knowing the limitations upfront saves time. These are tasks that no online PDF editor handles well, regardless of the tool:

• Reflow text after deleting or replacing it. A PDF stores text as positioned character sequences, not flowing paragraphs. The Edit Text and Redact tools remove the original text in an area, but surrounding text does not move: a shorter replacement leaves a gap, a longer one overlaps.
• Change fonts or styles of original text. PDFs embed font subsets — only the characters actually used — so you can't switch existing text from Arial to Times New Roman. New text you add uses the editor's standard font, in the size, color and weight you pick.
• Reflow content or change layout. Moving a text block to a different position, adjusting margins, changing column layouts, or resizing tables requires reflowing the entire document. This is a word processor operation.
• Edit the text inside a scanned PDF. A scanned page is an image. You can add content on top, but modifying the scanned text requires OCR first, then conversion to Word.

For all of these tasks, the workflow is: convert to Word, make changes, export back to PDF.

Tips for Professional-Looking Results

• Match sizes and weight. The biggest giveaway that a PDF was edited is mismatched typography. You can't pick the font family, so match the point size, color and bold/italic of the surrounding text.
• Use transparent PNGs for images. Logos, signatures, and stamps look significantly better with transparent backgrounds. A white rectangle behind your company logo on a gray background looks unprofessional.
• Zoom to 100% before finalizing. Edits that look aligned at 50% zoom often have visible offset at actual size. Always check at 100% before downloading.
• Keep a copy of the original. Always work on a copy. If an edit goes wrong, you can start over from the unmodified source.
• Compress after adding images. Each image you insert increases the file size. After editing, run the PDF through the PDF compression tool to bring the file size back down.
• Treat every edit as permanent. The editor writes your text, drawings, and images into the page content itself, not as a removable annotation layer — recipients cannot strip them off, and neither can you, so keep the original.
• Use consistent annotation colors. If your team reviews documents regularly, agree on a color scheme: yellow for suggestions, red for required changes, green for approvals. This speeds up the review cycle.
• Test on another device. Before sending an edited PDF to a client or colleague, open it on a different device or in a different PDF viewer. What looks right in one viewer may render differently in another.

Related Tools

• Edit PDF — Add text, images, annotations, and signatures
• PDF to Word — For rewriting content and layout changes
• Compress PDF — Reduce file size after editing
• OCR: PDF to searchable PDF — Make scanned PDFs searchable before editing
• Merge PDF — Combine multiple PDFs into one document
• Split PDF — Extract or remove specific pages