How to Sign a PDF on Your Phone or Computer

How to sign a PDF

• Open Sign PDF and add your document.
• Draw your signature with your finger or mouse.
• Tap the spot on the page where the signature belongs.
• Adjust the size, and choose whether to place it on every page.
• Download the signed PDF.

Tips for a neat signature

• Turn your phone sideways to get more room to draw.
• Draw slowly and keep the line smooth.
• Clear the box and try again until you are happy with it.

Is this signature legally valid?

The tool adds an image of your signature to the page. For many everyday documents, such as permission slips, simple forms and internal approvals, a visible signature is accepted. Some contracts or official processes require a certified digital signature issued by a recognised provider. If you are unsure, ask the person or office who asked for the document which kind they accept. We are not a legal service, so please check for important agreements.

Keeping your signature private

Your signature drawing exists only on your screen until you download the file. Do not share signed documents carelessly, since a signature image can be copied by anyone who gets the file.

Before you send

Open the signed PDF once to confirm the signature is in the right place. If you also need to fill in text fields, use PDF Forms first, then sign the filled file.

Common mistakes when signing

• Making the signature too large, so it covers printed text.
• Signing the wrong page or the wrong line.
• Sending an unsigned copy by mistake. Open the file after saving.
• Using a rough scribble that does not look like your usual signature when the receiver needs a match.

Signing a form that also needs typing

If the document has fillable fields, fill them first with PDF Forms and choose to lock the answers, then add your signature. Doing it in this order stops anyone changing the answers after you have signed.

Typed, drawn or image signature

There are three common ways to sign a PDF. You can draw your signature with a finger or stylus, type your name in a signature style font, or upload a picture of your real signature. Drawing on a phone screen is quick and looks natural. A photographed signature on white paper looks the most like your real one and can be reused for every document.

Making a good signature image

Sign with a dark pen on plain white paper, take the photo in good light and crop tightly around the signature. A clear background makes it easy to place on the page without a visible box. Keep the file small, because a signature does not need to be high resolution.

Store the image somewhere safe on your phone. Anyone who gets a copy of it can paste it into a document, so do not post it publicly.

Are electronic signatures valid?

In many countries an electronic signature is accepted for ordinary agreements such as rental forms, offer letters, consent forms and invoices. Some documents, such as certain property transfers or court filings, may have special rules and require a specific method or a witness. If you are unsure, ask the person or organisation requesting the signature what they accept.

A signature added with a free tool is a visual signature. It does not provide the legal identity checks that a certified digital signature service does, so for high value contracts ask whether a certified service is required.

Frequently asked questions