How to sign a PDF online for free

  1. Open the PDF. Tap Choose PDF and pick the file. It opens in your browser and every page is shown below.
  2. Create your signature. Draw it in the box, type your name, or upload a photo of your signature on white paper. Pick black or blue ink.
  3. Place it. Tap Add signature to the page, then tap where it belongs. Drag it to adjust and drag the round corner handle to resize. Add text or the date the same way.
  4. Fill in the fields. If the PDF has fillable fields, they are listed above the pages — type into them. Leave Flatten ticked to lock the fields and signature into the page.
  5. Download. Tap Create signed PDF, then Download. Open the file once to check the signature sits where you expect before you send it.

What it does

  • Three ways to sign: draw with a finger, pen or mouse; type your name in a handwriting font; or upload a photo of your signature on paper (the white background is removed)
  • Place the signature on any page, then drag to move it and drag the corner to resize
  • Add text and today’s date anywhere — handy for forms with no fillable fields
  • Fills the PDF’s own form fields (text boxes, checkboxes, drop-downs) and can flatten them so they can’t be changed
  • Keyboard accessible: arrow keys move a placed item, Shift+arrows resize, Delete removes
  • Runs entirely in your browser — the PDF is opened in memory and never uploaded

What this tool does

It puts a signature on a PDF and fills in the PDF’s form fields without sending the file anywhere. You open the PDF, make a signature by drawing, typing or uploading a photo of it, tap the spot on the page where it goes, and download a new PDF with the signature, any text you added, and the filled fields written into it. Nothing to install, no account, no watermark.

How it works, and what that means for your file

The page loads two open-source libraries: pdf.js, which draws the pages so you can see where to sign, and pdf-lib, which writes the new PDF. Your signature is turned into a transparent PNG image by the browser and placed on the page at the size you chose. Form fields are filled through the PDF’s own form structure, so a checkbox stays a checkbox. The original file is never uploaded: it is opened in your browser’s memory and the signed copy is created there.

Two honest consequences. The signature is an image, so it can be copied by anyone who has the signed file — the same is true of a scan of a paper signature. And text you add with Add text is also an image, so it isn’t searchable; text typed into real form fields stays real text.

Is an electronic signature like this legally valid?

For a lot of everyday paperwork — a permission slip, a lease renewal, an HR form — yes. In the United States, the ESIGN Act (15 U.S.C. § 7001) says a signature or contract “may not be denied legal effect, validity, or enforceability solely because it is in electronic form”, and it defines an electronic signature as a sound, symbol or process attached to a record “with the intent to sign the record”. In the EU, the eIDAS Regulation (Article 25) says an electronic signature can’t be refused as evidence just because it is electronic — but only a qualified electronic signature, made with a certificate from a qualified trust service provider, has the same legal effect as a handwritten one in every member state.

A drawn, typed or photographed signature is a simple electronic signature. It is not a certificate-based digital signature, it doesn’t prove who signed, and it doesn’t lock the document against later changes. Some documents are outside these rules altogether — US federal law excludes wills, codicils and testamentary trusts, and court orders, foreclosure and eviction notices have their own requirements. When it matters, ask the person who sent you the document what kind of signature they accept.

Sign a PDF on iPhone without any tool

On an iPhone you don’t need a website at all: Preview (iOS 26 and later), Files and Mail all have Markup with an Add Signature button, and Preview can fill in form fields. The full steps, including saving several signatures and fixing forms that won’t take text, are in how to sign a PDF on iPhone. If you need to edit the PDF first, see how to edit a PDF on iPhone; to combine the signed form with other pages, use merge PDF.

Limits

  • Encrypted or password-protected PDFs can’t be changed; remove the protection first.
  • Very large PDFs (hundreds of pages, or over about 100 MB) can run out of browser memory, especially on a phone.
  • Some forms use a font that can’t show every character; if flattening fails with non-Latin text, untick Flatten or add the text as a text stamp.
  • XFA forms (an older Adobe-only form type) are not supported by pdf-lib; their fields won’t appear.

Keep the signed copy

Once a signed form is back with whoever asked for it, it’s easy to lose your own copy in Downloads. Paperlock, our iPhone app, keeps it in a Face ID-locked vault, reads what the document is and the dates in it, and finds it again when you ask — “show me the lease I signed in March”. It doesn’t sign or fill in forms itself; that’s what this page is for.