Four ways to sign a PDF, and why the difference matters
If you need to sign PDF files every day, at a bank counter, a car rental desk, a clinic reception or a real estate office, the method you choose decides how much evidence the signed file carries. Online tools make it easy to put a mark on a page. They don’t all record who made that mark, or prove the document wasn’t changed afterwards.
There are four common ways to put a signature on a PDF:
- Typed or image signature. You type your name in a script font or insert a picture of your signature. Quick, but it is only a picture. Anyone with the image file can reuse it.
- Drawn with a mouse, touchpad or touchscreen. Most PDF readers let you draw a signature in a box. The result is again a picture of strokes, with no data about how they were written.
- Handwritten with a pen on a signature pad or pen display. Signing software such as Wacom sign pro PDF captures the visible signature together with the pen data behind it, then seals the document so later changes can be detected.
- Certificate-based digital signature. The PDF is signed with a digital certificate (a private and public key pair) that ties the signature to a verified identity. There may be no visible handwriting at all.
The first two suit low-risk internal paperwork. For customer contracts, account forms and declarations, most organisations want the third, the fourth, or both.
What a pen-captured PDF signature records
When a customer signs with a Wacom pen in sign pro PDF, the software saves more than the ink you see on the page. According to Wacom’s quick start guide for sign pro PDF:
- Pen data. Signatures are saved with pen data in Wacom’s Forensic Signature Store (FSS) format, which works with Wacom verification applications, or in an ISO standard signature format that third-party applications can read.
- Signer details. Each signature stores the signatory name and the reason for signing, and can show them under the signature together with the date and time of signing.
- Tamper evidence. Wacom states that documents signed and saved in sign pro PDF for Windows are secured with a cryptographic hash, so any later change to the document can be detected.
- Document certification. You can make the first signature certify the document and choose whether to allow form filling, signing and commenting afterwards, form filling and signing only, or no changes at all.
- Optional encryption. The signature data can be encrypted with a digital certificate, so only the holder of the matching key can extract it.
That pen data is what lets a document examiner or verification software compare a disputed signature with a known one. We explain how that comparison works in the benefits of biometric signature verification, and why banks keep reference signatures in specimen signature meaning.
What you need to sign PDF files with a Wacom pen
A working setup has three parts.
1. A Windows PC
sign pro PDF for Windows runs on the staff workstation. It opens, fills, signs and saves the PDF, and includes a virtual printer driver, so you can create a PDF from any Windows application that can print.
2. A pen device for the signer
- Signature pad. A compact pad such as the Wacom STU-430 or the colour Wacom STU-540 captures the signature only. The document is shown on the staff monitor.
- Pen display. A signature display such as the Wacom DTU-1141B shows the whole PDF to the customer, who reads, fills in and signs on the same screen.
If you are unsure which suits your counter, our signature pad vs signature display guide compares the two.
3. A signing certificate
On first launch, sign pro PDF asks for a digital certificate used in the signing process. You can load one from a file or the Windows certificate store, or let the software create one. Wacom notes that a certificate created by the software is self-signed, so recipients cannot verify the signer’s identity from it, and recommends a certificate from a certification authority if signed documents go to many different recipients.
A ready-made bundle such as the Wacom STU-430-CH2 signature set combines a pad with the software.
How to sign a PDF with a Wacom signature pad, step by step
1. Install the software and the pad driver
During installation, sign pro PDF offers to install the driver for Wacom STU tablets. Select it if you will connect an STU signature pad. When the pad is connected and the software starts, an idle image appears on the pad’s screen.
2. Choose the licence mode
Standard mode lets you sign, annotate and fill PDF forms. Extra features such as templates, the ISO format with signature encryption, handwriting recognition for form filling and API support need a purchased licence. Trial mode lets you test them, but adds a watermark until a licence is installed.
3. Open the PDF and fill the form
Open the file in Sign & Fill. Check boxes, radio buttons, date fields and text fields can be completed with the mouse and keyboard.
4. Place and capture the signature
Click Sign, then draw a rectangle where the signature should go, or click a signature field already placed in the document. The signature is captured on the pad and appears in the rectangle. With a licence that includes Authoring, you can save templates with signature fields in fixed positions, so staff don’t have to place them each time.
5. Save, print or share
Save the signed file, print a copy for the customer or share it by email. The signed PDF opens in standard PDF viewers.
For a full contract read and signed on a pen display at the counter, see our guide on how to sign contract documents in person.
Common problems when you sign PDF files with a pad
- The pad does nothing in Adobe Acrobat. Wacom has discontinued its sign pro plug-in for Adobe Acrobat and says it is no longer available. Use the sign pro PDF application instead, or integrate the pad into your own software with Wacom’s SDKs.
- The pad pen won’t move the mouse pointer. This is expected. Wacom notes that the STU pad pen has no control over the Windows mouse pointer, so tools like freehand ink annotations need the mouse or a pen display.
- A government or bank form won’t open. Dynamic XFA forms are not standard PDF forms. Wacom says they cannot be displayed by most viewers, including sign pro PDF. Ask the issuer for a standard PDF form.
- A watermark appears on the signed file. The software is in Trial mode. Switch back to Standard mode or install the purchased licence.
- The recipient sees an unverified signer. The document was signed with a self-signed certificate. Use a certificate from a certification authority.
Connecting PDF signing to your own systems
When signing happens inside a core banking, policy administration, rental or hospital system, staff shouldn’t have to save and reopen files by hand. The Wacom sign pro PDF API lets an existing application pass a PDF to sign pro PDF for signing. Wacom describes a Windows flow in which a cloud-based system hands the PDF to the app, the user signs and completes it, and the PDF is saved to a specified server before control returns to the cloud system.
Developers who want signature capture inside their own interface can use the Wacom Ink SDK for signature. For a broader look at the software, read our Wacom sign pro PDF guide.
Is a signed PDF legally valid in the UAE?
It depends on the type of signature and the document. The UAE’s Federal Decree-Law No. 46 of 2021 on Electronic Transactions and Trust Services says an electronic signature cannot be refused as evidence just because it is electronic. It also defines advanced and qualified electronic signatures, and gives a qualified signature, created with a qualified certificate from a TDRA-licensed trust service provider, the same legal effect as a handwritten one. Some document types can be excluded from electronic signing.
A pen-captured signature sealed into a PDF gives strong evidence of who signed and that the file hasn’t changed since. It does not, on its own, turn a signature into a qualified one, and the device alone doesn’t make a document legally valid. Confirm the requirement for each document type with your legal or compliance team.
Where UAE organisations sign PDF forms by hand
Typical documents include account opening and KYC forms at banks and exchange houses (see electronic signatures for UAE banking), postpaid contracts at telecom stores, rental agreements at car rental desks, tenancy contracts at real estate offices, insurance proposal and claim forms, and admission and consent forms at hospitals and clinics (see paperless signature solutions for UAE hospitals).
eTOP Trading is an Authorized Wacom Solution Provider and system integrator in the UAE. We help teams choose the right pad or pen display, set up sign pro PDF and connect signing to their existing systems.
Frequently Asked Questions
How do I sign a PDF with a handwritten signature?
Connect a Wacom signature pad or pen display to a Windows PC, open the PDF in signing software such as Wacom sign pro PDF, click Sign, place the signature box and sign with the pen. Then save, print or email the signed file.
Can I use a Wacom signature pad in Adobe Acrobat?
Not directly any more. Wacom has discontinued its sign pro plug-in for Adobe Acrobat. Wacom recommends the sign pro PDF application for signing, or its API and SDKs for integrating the pad into other software. PDFs signed in sign pro PDF can still be opened in Acrobat and other PDF viewers.
Is a PDF signed on a signature pad legally valid in the UAE?
It depends on the document. Under Federal Decree-Law No. 46 of 2021, an electronic signature cannot be refused as evidence just because it is electronic, but some transactions require a qualified signature from a licensed trust service provider and some document types are excluded. Check each document type with your legal or compliance team.
Why can't I open some PDF forms in sign pro PDF?
Dynamic XFA forms are not standard PDF forms. Wacom says most viewers, including sign pro PDF, cannot display them. Ask the issuer for a standard PDF version of the form.
Do I need a digital certificate to sign PDF files with sign pro PDF?
sign pro PDF uses a certificate in the signing process and can create a self-signed one for you. Wacom recommends a certificate from a certification authority if you send signed documents to many recipients, because a self-signed certificate does not let them verify the signer's identity.