How to Sign a PDF Online for Free (No Upload, No Account)

To sign a PDF with PixelTools' [Sign PDF](/sign-pdf) tool, open your file, add a signature by drawing it with your mouse or trackpad, typing your name in a cursive-style font, or uploading a photo of your handwritten signature, then drag it onto the page and resize it to fit. When you're done, the tool flattens the signature directly into the PDF's page content and gives you a download.

'Flattening' means the signature stops being a separate movable layer and becomes part of the page itself, the same way text or an image already on the page is part of it. That's what makes the result behave like a normal signed document when opened in any PDF viewer, rather than a form field that could be edited or removed later.

The whole process — rendering the PDF, placing the signature, flattening it, rebuilding the file — runs in your browser using pdf-lib compiled to WebAssembly. Nothing is uploaded to a server at any point, which matters if the document is a lease, an NDA, or anything else you'd rather not hand to a third-party service.

You have three ways to create a signature: draw it freehand with a mouse, trackpad, or touchscreen; type your name and have it rendered in a signature-style font; or upload an image of your actual handwritten signature (signed on paper and photographed or scanned, or drawn in another app and exported as PNG).

Drawn signatures look the most natural but take a steadier hand on a trackpad than on a touchscreen. Typed signatures are the fastest option and look clean and consistent, though they read as less personal. Uploaded images give you your real signature at full fidelity, and work well with a transparent-background PNG so no white box appears around it.

Once created, the signature can be reused and repositioned on multiple pages in the same session before you flatten and download — useful for documents that need initials on every page plus a full signature at the end.

After creating a signature, drag it anywhere on the page and resize it using the corner handles until it fits naturally next to a signature line or date field. You can zoom in on the page for precise placement on dense forms, and add the same signature to more than one page in a single pass.

Nothing is permanent until you flatten. Flattening merges the signature into the page's actual content stream — the same operation that happens when you flatten a layered image — so the output is a standard, single-layer PDF page rather than a document with an editable overlay sitting on top of it. This is also why the signed PDF opens correctly and looks identical in every viewer, from Adobe Reader to a phone's built-in PDF app, instead of relying on that viewer supporting interactive form fields.

Signing isn't the only thing you'll want to do to a PDF before sending it back. [Annotate PDF](/annotate-pdf) uses the same overlay-and-flatten approach to add free text boxes, highlight passages, and draw rectangles or arrows to point at specific content — the kind of markup you'd normally do by printing a document, marking it up by hand, and re-scanning it.

Typed text boxes are useful for filling in blanks on a form that doesn't have real fillable fields. Highlights work well for flagging clauses in a contract before a call to discuss them. Rectangles and arrows are the fastest way to draw attention to a specific line, figure, or signature block without writing a paragraph of explanation.

Like signing, every annotation gets flattened into the page when you export, so the markup can't be accidentally dragged, deleted, or hidden by whoever opens the file next — it's simply part of the page.

Both tools do the entire job — parsing the PDF, rendering pages to the canvas, compositing your signature or annotations, and rebuilding the output file — inside the browser tab, using pdf-lib compiled to WebAssembly. There's no server-side processing step, which means there's no upload, no server-side copy of your document even temporarily, and no account or email address required to use either tool.

This matters most for documents you can't casually hand to a third party: signed contracts, tax forms, medical paperwork, ID copies. The tradeoff is that processing speed depends on your device rather than a server's, which is rarely noticeable for typical multi-page PDFs but can matter on a very large or image-heavy file on an older machine.

Be clear-eyed about what Sign PDF actually does: it lets you place a visual representation of your signature onto a PDF you already have and flatten it in — the same outcome as printing, signing by hand, and re-scanning, just faster. It does not do what dedicated e-signature platforms like DocuSign, Adobe Sign, or PandaDoc do: there's no audit trail or certificate of completion, no identity verification of the signer, no multi-party routing or email-based signing requests, and no built-in guarantee of compliance with e-signature laws like ESIGN or eIDAS.

If you're the only signer and you're applying your own signature to your own copy of a document — a form, a permission slip, an internal memo — this is a fast, private way to do it. If you need a legally binding signature workflow involving other parties, sequential approvals, or verifiable proof of who signed and when, use a platform built for that purpose instead.