Free Sign PDF

Worked example

Choose "Try a sample". It opens sample-agreement.pdf, a one-page agreement (595 × 842 points) with the lines "Client name:", "Signature:" and "Date:". Under "Jump to a signature line" the tool lists "Page 1: Signature:", because it found that label followed by a blank line. Under "1. Your marks" press "Set up" on Signature, type Jane Smith, and the initials box fills itself with JS ("Filled in from your name — edit it if you like."). Press "Use this Signature", then press "Page 1: Signature:". The signature lands on the line at the default size of 22% of the page width, about 131 points, while initials default to 8%, about 48 points. Press "Sign PDF", then "Download signed PDF". The file is called sample-agreement-signed.pdf, and a line under the page shows that name and its size.

Which settings to use, and the limits

• Set up a signature and initials once. Under "1. Your marks", both "Signature" and "Initials" can be made by typing, drawing or uploading ("Type", "Draw", "Upload"). Typing offers three handwriting styles and shrinks a long name to fit, and Cyrillic and Arabic letters fall back to script faces that cover them. Drawing uses a 600 × 200 pad. Each mark is trimmed to its ink and saved in this browser ("Saved on this device only."), so it is there next time. On a shared computer press "Forget my signature".
• Sign from a photo of your own handwriting. In "Upload" choose "Choose a signature image (PNG or JPG)" or "Take a photo". Sign with a dark pen on plain white paper and fill the frame. With "Remove the paper background" ticked, which is the default, the tool lifts the ink off the paper, evens out shading, drops specks and recolours the ink to near-black, or to blue if the pen was clearly blue. An image that is already 5% or more transparent is used as it is. Photos are scaled to at most 1,600 px on the longest side first.
• Place, move, resize and undo. Click the page to place the active mark, drag it to move it and drag its corner handle to resize it. The "Size" slider for a signature or initials runs from 4% to 50% of the page width. "Quick place" has "Bottom left", "Center" and "Bottom right" for keyboard use. Select an item and press Delete to remove it, or Escape to deselect. "Undo", or Ctrl+Z (Cmd+Z on a Mac), steps back through up to 60 changes.
• On a long contract, jump to the lines and repeat initials. Under "Jump to a signature line" the tool lists up to 12 places, found on the first 40 pages, where it finds a short line with a label such as signature, signed, sign here or initial (or the same word in another language), usually followed by a blank line. Pressing one goes to that page and drops the active mark there. It reads the PDF's text, so a scanned PDF with no text layer shows no list. After you place a mark once, "Add this Initials to all 12 pages" (12 stands for your page count) copies it to the same spot on every other page.
• Fill in the form as well as signing. Under "Fill in the form" choose "Text", "Date", "Tick" or "Cross" and click where it goes. Text and dates can be 6 to 48 pt, ticks and crosses 6 to 60 pt. "Date" has a "Today" button and two formats, which for 5 November 2026 in English read 11/05/2026 or November 5, 2026. Western European text is added as real, selectable PDF text in Helvetica. Text in other scripts, such as Cyrillic, Arabic or Chinese, is drawn as an image so it displays correctly, but it cannot be selected.
• Decide about form flattening, and watch the file size. When the PDF has fillable fields, the box "Flatten the form fields in this PDF" appears, ticked by default: "Turns filled-in fields into fixed page content so they can't be edited or moved." Leave it ticked for a final copy and untick it to keep the fields fillable. If the signed file is larger than 10 MB, the page warns that many email providers and upload portals reject it and points to Compress PDF. Once the file is signed, buttons for "Compress PDF" and "Password protect" appear under its name, and "Share…" where your browser supports sharing files.

Common problems and how to fix them

It says "Couldn't open this PDF. It may be corrupt or password-protected."

This is the failure recorded most often for this tool. The PDF engine could not open the file, so it may be damaged, cut short by an interrupted download, or not really a PDF. Download it again from the source, or open it in a PDF viewer and print it to a new PDF, then add that copy. If the page says "This file changed or moved after you picked it — please choose it again." instead, pick the file again, and download it to the device first if it lives only in a cloud drive.

It says "This PDF is password-protected, so it can't be opened for signing. Remove the password first, then try again."

Under the message the page shows "Send this file to another tool" with an "Unlock PDF" button. It hands the same file to the unlock tool inside your browser, and the unlocked copy can be passed back. Remove the password there, return, and sign the unlocked copy.

It says "Create a signature first, then click on the page to place it."

You clicked the page before the active mark existed. Press "Set up" under "Signature" or "Initials", make it, and press "Use this Signature". The same kind of message appears for the other tools: "Type the text first, then click on the page where it should go." for a "Text" field, and "Place it once on this page first, then we can copy it to every page." for the all-pages button.

It says "Couldn't find a signature in that photo. Sign on plain white paper with a dark pen, fill the frame, use good light, and try again."

After the paper was removed, fewer than 20 pixels of ink were left. Retake the photo with the signature large in the frame, a dark pen, plain white paper and even light. If you already have a signature as a PNG with a transparent background, upload that and it is used as it is. If the message is "Couldn't read that image. Try a PNG or JPG file.", the browser could not open the file, so export it as PNG or JPG first.

It says "Couldn't create the signed PDF. Please try again."

The marks were placed, but building the file failed, for example because the PDF has an unusual structure that the writer cannot rewrite. Press "Sign PDF" again. If it repeats, make a fresh copy of the PDF by opening it in a viewer and printing to PDF, and sign that.

How it compares

This tool puts a visible signature image on the page. The page itself says that is usually enough for everyday paperwork such as rental and gym forms, permission slips and internal approvals. It is not a certificate-based digital signature: the file does not record who signed or when, and a later change is not detected. If the recipient asks for a qualified or certified signature (the page gives eIDAS in the EU and some government, tender or court filings as examples), you need a service that issues one. It also does not send the document to other people to sign or keep an audit trail. Printing, signing by hand and scanning gives the same look, but turns every page into a picture; here the original pages stay as they were and the marks are added on top.