Printing a document to sign it and then scanning it back is time-consuming and degrades quality with each round trip. Modern browsers make it completely unnecessary. PDFWhisk's PDF signing tool lets you draw your signature, type it, or upload an image of it, then place it precisely on any page, all in the browser, with no upload to any external server.
Three ways to add a signature to a PDF
PDFWhisk supports three signature input methods, each suited to different situations.
Draw your signature
On a touchscreen, a tablet, a phone, or a laptop with a touchscreen, this is the most natural option. Tap the signature area and draw your normal signature with your finger or stylus. The result is a vector image that scales cleanly to any size on the page. On a desktop without a touchscreen, you can draw with the mouse, though most people find that harder to make look natural.
Type your name
If you need a clean, readable signature, for internal approvals, acknowledgement forms, or lower-formality documents, typing your name in a cursive font is a practical option. It is consistent every time and readable at small sizes. Many people use this for routine approvals where a hand-drawn signature is not specifically required.
Upload an image
If you have a scan or photograph of your physical signature saved as a PNG or JPG, you can upload it directly. The tool strips the background from the image so it sits cleanly on the PDF without a white box around it. This gives the most natural-looking result if you need the signature to look like an original handwritten sign-off.
How to place and resize the signature
Once your signature is created, you drag it into position on the page. You can resize it by dragging the corner handles, and move it anywhere on the page. Multi-page documents let you choose which page or pages the signature appears on, useful for contracts where you need to sign at the bottom of each page and also on the final signature line.
Is a PDF signature legally valid?
This is a frequently asked question with a nuanced answer. In the UK, a simple electronic signature, including a typed name or a scanned handwritten signature placed on a document, is legally valid for the vast majority of everyday transactions under the Electronic Communications Act 2000. This includes employment contracts, service agreements, NDAs, and most commercial contracts.
There are exceptions. Certain documents require a higher standard of authentication, for example, deeds (such as transfers of property), wills, lasting power of attorney forms, and documents requiring a witness. For these, a wet ink signature witnessed in person is still required by law. If you are unsure whether your document falls into this category, check with a solicitor before signing electronically.
For business-to-business contracts and internal approvals, electronic signatures are standard practice and widely accepted.
Signing on an iPhone or Android phone
The tool works well on mobile. Open pdfwhisk.com/sign-pdf in Safari on iPhone or Chrome on Android. Draw your signature with your finger on the touch input area, then drag it into position on the page. The signed PDF saves to your files or can be shared directly from the browser share menu.
Signing on a phone is particularly useful when someone sends you a document to sign while you are away from your desk. Rather than saying you will do it later, you can sign and return it immediately without needing a printer or scanner.
Keeping your signature private
Because PDFWhisk processes everything locally, your signature image and your document never leave your browser. This matters for sensitive documents: employment contracts, financial agreements, and legal documents often contain personal details that you would not want passing through a third-party server. There is no account to create, no cloud storage involved, and no retention of your files or signature data.
What about witnessed signatures?
If a document requires a witness, a signature from someone who can confirm they saw you sign, an electronic signature added in PDFWhisk is not sufficient on its own. The witness would also need to add their own signature electronically in a way that records their identity, or you would need to sign physically in their presence. For witnessed documents, specialist e-signature platforms with identity verification are more appropriate.
After signing: sending the document
Once you have downloaded the signed PDF, you can send it by email or through whatever platform the other party is using. The signature is embedded in the PDF as a permanent element, it will display correctly in any PDF viewer on any device. The recipient does not need any special software to see it.
If the document also needs compressing before sending, for example an email attachment limit, use PDFWhisk's compression tool on the signed file. This reduces file size without affecting the signature.