How to Sign a PDF Online

Sign a PDF in your browser by drawing your signature or using an image of it. Learn how visual and digital signatures differ and how to place a signature well.

Visual signatures and digital signatures

The word signature means two quite different things in the PDF world, and it is worth knowing which one you need before you start.

A visual signature, sometimes called an electronic or handwritten signature, is an image of your signature placed on the page. It looks like ink on paper and shows your intent to sign, the same way a scanned signed page does. It is quick to create and is accepted for many everyday documents, such as permission slips, delivery confirmations, quotes, rental applications and internal approvals.

A digital signature is a cryptographic seal created with a certificate. It does not have to look like handwriting at all. Instead, it lets PDF software verify who signed the file and confirm that nothing changed after signing. Some contracts, official filings and regulated industries require this kind of signature, usually created with dedicated signing software or a certificate issued to you.

Sign PDF on QuickConvertOnline creates visual signatures only. If a recipient asks for a certificate-based or qualified digital signature, use the process they specify. When in doubt about what is acceptable for a particular document, ask the person or organization you are sending it to.

How to sign a PDF step by step

1. Open Sign PDF and drop your PDF onto the page, or select Choose PDF. Enter the password first if the file is protected.
2. Draw your signature in the signature box with a mouse, trackpad, finger or stylus. Select Clear signature to try again. To use an existing signature image instead, select Choose image.
3. Pick an ink color. Dark blue or black looks most natural on printed documents.
4. Click the page thumbnail you want to sign, then click or drag on the large page preview to position the signature. Fine-tune it with the X, Y, Scale, Opacity and Rotation controls.
5. Select Apply, check the preview of the result and download the signed PDF.

Tips for a signature that looks right

Drawing with a mouse rarely produces a natural signature. A finger on a phone or tablet, a stylus or a laptop trackpad usually gives smoother lines. Write larger than you think you need, filling most of the box: the signature is scaled down when you place it, which hides small wobbles.

For the most authentic result, sign a sheet of white paper with a pen, photograph or scan it in good light, crop it tightly with the Image cropper and choose it with Choose image. A PNG with a transparent background looks best, because no white box appears over lines or text underneath. Keep the Scale low enough that the signature fits the signature line rather than spilling over printed text.

Signing several pages or a specific page

When you click a page thumbnail, the Pages field is set to that page, so the signature goes exactly where you placed it. To initial every page of a contract, clear the Pages field, which applies the signature to all pages at the same relative position, or enter a list such as 1, 3-5. Position is measured as a percentage of the page, so the signature lands in the same spot on pages of the same size.

Filling in the rest of the document

Most documents need more than a signature: a printed name, a date, perhaps a few checkboxes. If the PDF has interactive form fields, fill them first with Fill PDF forms, which supports text fields, checkboxes, radio buttons, dropdowns and lists and keeps them editable. For PDFs without fields, use Add text to PDF to type your name and the date anywhere on the page, with your choice of font size and color.

Some forms include a dedicated digital signature field. Fill PDF forms lists it as a signature field but cannot fill it, because that field is meant for a certificate-based signature. You can still place a visual signature next to it with Sign PDF if the recipient accepts that.

Documents that are already digitally signed

If someone has already applied a digital signature to the PDF, any change to the file, including adding your visual signature, can make their signature show as invalid in PDF readers. Sign PDF detects existing digital signatures and shows a warning. In that situation, ask the sender how they want you to sign, because their workflow may require a specific signing tool.

Keeping your signature private

Your signature is drawn and applied entirely in your browser. It is not uploaded, not stored on a server and not saved between visits, so you draw or choose it again each time. Keep in mind that anyone who receives a signed PDF can see the signature image, just as with a scanned paper document. If the document is sensitive, encrypt it with Protect PDF before sending, and share the password through a different channel.

Frequently asked questions

Is a signature drawn in Sign PDF legally binding?

Many jurisdictions recognize electronic signatures for many types of agreements, but the rules depend on the country and the document. Some documents require a certificate-based signature, witnesses or wet ink. Check with the recipient or a legal adviser for anything important.

Can I sign on a phone?

Yes. Signing with a finger on a touch screen often looks more natural than using a mouse, and the tool works in current mobile browsers.