How to Add Text, Comments & a Signature to a PDF
Fill in a form, leave a note for a colleague to review, or sign a document — directly on the page, in your browser, free and without creating an account.
Three ways to mark up a PDF
RedPDF's editor gives you three independent tools you can mix on the same page: a text tool for typing directly onto the document — useful for filling in a form field that isn't a real fillable form, or adding a note under a heading; a comment tool that drops a sticky-note style annotation, handy for flagging something for a colleague without altering the underlying page; and a signature tool that places an image of your signature wherever you click, then lets you drag and resize it to fit.
All three place their content as an overlay directly on the rendered page, so what you see while editing is what ends up in the downloaded PDF — no separate "preview" step that surprises you later.
Adding text, a comment or a signature, step by step
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1. Open your PDF
Go to the Edit & Merge tool and drop in the document you want to fill in, annotate or sign.
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2. Pick a tool
Choose Text, Comment or Signature from the toolbar. For a signature, you'll first select a JPG or PNG photo of your signature.
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3. Click to place it
Click anywhere on the page preview to drop the text box, comment or signature there, then drag it into the exact spot and, for a signature, resize it using the corner handle.
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4. Repeat and download
Move to other pages using the page list, add as many elements as you need, then click Download PDF to save the finished document.
A note on signatures
The signature tool places a picture of your signature onto the page — the same visual result as printing a document, signing it by hand and scanning it back in, just without the printer. It is not a certified or cryptographic digital signature (the kind that legally verifies who signed and that the file hasn't since changed), so for documents that specifically require that level of certification, you'll want dedicated e-signature software instead. For everyday paperwork — signing a form, initialing a page, approving a draft — an image signature is exactly what most people already do by hand.
To get a clean signature image, sign your name on plain white paper in dark ink, photograph or scan it in good light, and crop it fairly close before uploading — the tool will still let you resize it precisely once it's placed on the page.
Edit & sign PDF — frequently asked questions
Can I edit text that's already in the PDF?
The text tool adds new text on top of the page rather than rewriting existing text within the document — the same approach as filling in a printed form by hand. This covers the vast majority of real-world needs: filling gaps, adding notes, initialing pages.
Will my comments be visible to whoever I send the PDF to?
Yes — comments are placed directly onto the page as part of the document, so anyone who opens the downloaded PDF will see them exactly where you put them.
Can I use a scanned or photographed page as a signature?
Yes, any JPG or PNG works, including a photo taken on your phone. A plain background and good lighting give the cleanest result once it's placed and resized on the page.
Is this a legally binding digital signature?
No — it places an image of your signature rather than a certified digital signature with cryptographic identity verification. For everyday paperwork it looks and works exactly like signing by hand and scanning, but if a specific document requires a certified e-signature, use dedicated e-signature software instead.