Sign PDF Free Online – Add Your Signature
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Sign PDF lets you place a picture of your signature onto any page of a PDF, either by drawing it with your mouse or finger or by uploading a photo of your real signature and letting an in-browser AI model strip its background automatically. It's worth being precise about what this produces: the result is a visual signature — an image stamped onto the page — not a cryptographic digital signature with a certificate that a signature-validation tool can verify. There's no “type your name” option either; drawing and uploading an image are the only two ways to create one.
That makes it a good fit for documents you're comfortable countersigning with your usual handwritten-look signature — offer letters, consent forms, quotes, informal agreements — sent back without printing and rescanning. For a contract that specifically requires a verifiable cryptographic signature with an audit trail, this isn't that tool; check what the recipient actually requires before relying on it for something legally load-bearing. Everything happens in your browser: the PDF and your signature image are never uploaded anywhere.
How it works
1. Upload PDF
Drop a PDF up to 100 MB. A file that needs a password to open is rejected with a message to unlock it first — there's no password field in this tool.
2. Draw or upload your signature
Choose “Draw Signature” to sign on a canvas with your mouse or finger (pick from four ink colors and three pen sizes), or “Upload Image” to use a photo of your signature — its background is removed automatically before you continue.
3. Place it on the page
Click anywhere on a page to drop your signature there, drag it to reposition, or drag the corner handle to resize it. Each page gets its own independent position unless you turn on “Apply to all pages.”
4. Apply and download
Once at least one page has a placement, press “Apply & Download.” The output keeps the original filename with “-signed” added before .pdf.
When you'd use it
Returning an offer letter or NDA by email
Sign the last page and send it straight back as a PDF attachment instead of printing, signing on paper, and scanning it again.
Countersigning a rental or vendor agreement
Place your signature on the specific line or block a landlord or vendor sent as a PDF, without needing separate e-signature software or an account.
Signing a college or internship consent form
Forms that just need your signature and don't require a formal cryptographic e-signature process can be signed and returned the same day from a phone or laptop.
A freelancer signing a quote before sending it
Add your signature to a quote or invoice PDF before emailing it to a client, keeping the whole exchange to a single file with no printer involved.
A visual signature, not a cryptographic one
When you press Apply, the tool converts your drawn or uploaded signature to a PNG image and draws it directly onto the PDF page at the position and size you chose — the same mechanism as stamping a picture onto the page. There's no PKI certificate, no document hash, and no tamper-evidence added; a signature-validation panel in Acrobat or similar software won't show this as a verified digital signature, because it isn't one.
Legal recognition of a signature like this varies by country and by what the document itself requires — many everyday agreements accept a visual signature image without issue, but a contract that explicitly demands a certificate-based digital signature needs different software entirely. If you're unsure which category your document falls into, that's worth checking before you rely on this for something with real stakes.
Drawing vs. uploading your signature
Draw mode gives you a blank canvas with a transparent background, four preset ink colors, and three pen sizes — it captures whatever you draw with a mouse or touchscreen and nothing else. Upload mode accepts any image file and automatically removes its background using an AI model that loads only when you pick this option, so the first upload takes a little longer than drawing while the model downloads. If background removal fails for a particular image, the tool falls back to using your original photo as-is and shows a warning rather than blocking you.
Placing your signature across multiple pages
Every page you place a signature on keeps its own independent position and size — clicking to place, then dragging or resizing, only affects the page you're currently viewing. The “Apply to all pages” toggle becomes available once you've placed the signature on at least one page, and turning it on copies that single position to every page in the document instead of requiring you to place it on each one individually.
Frequently asked questions
Is this a legally binding digital signature?
It's a visual signature image stamped onto the page, not a certificate-based cryptographic digital signature. Whether that's sufficient depends on your document and jurisdiction — for anything requiring formal verification, use software built for cryptographic e-signatures instead.
Can I type my signature instead of drawing or uploading it?
No. The tool only supports drawing with your mouse or finger, or uploading an image of your signature — there's no typed-name signature style.
What happens if the automatic background removal doesn't work well?
If it fails, the tool falls back to your original uploaded image and shows a warning message. You can still place and apply that image as your signature.
Can I put the same signature on every page automatically?
Yes, but only after you've placed it manually on at least one page first — the “Apply to all pages” toggle then copies that position to the rest of the document.
Does each page need a separate signature placement?
By default, yes — each page you sign keeps its own independent position and size. Turn on “Apply to all pages” if you want one placement mirrored everywhere.
Can I sign a PDF that requires a password to open?
No. A password-protected PDF is rejected on upload with a message to unlock it first at /pdf/unlock, then bring the unlocked file back here.