A PDF form with text fields for name, date, address, and comments is complete except for the most important element: a place for the recipient to sign. Without a designated signature field, the recipient must either print the form, sign it physically, and scan it back to digital, breaking the all-digital workflow, or attempt to place a signature image somewhere on the page without a clear target location, hoping it lands in the right spot.
A signature field tells the recipient exactly where to sign and provides the tools to do it digitally. The field is a container that accepts a digital signature, a typed name, or a signature image, and locks it in place.
Adding a fillable Sign PDF signature field to a form involves using a PDF form editor to place a digital signature field at the designated signature location, and optionally configuring it to guide the recipient's signing experience. WukongPDF's PDF Forms tools support signature field creation, and the steps below cover adding signature fields that make your forms fully digitally signable.
Placing a Digital Signature Field on the Form
In Adobe Acrobat Pro, open the Prepare Form tool. Acrobat automatically detects existing form fields and enters form editing mode. From the toolbar at the top, select the Digital Signature tool, which appears as a pen icon or is labeled Add a Signature Field. Click on the page where the signature should be placed and drag to draw a rectangle that defines the signature area. The rectangle should be large enough to accommodate a natural handwritten signature, typically about 2 inches wide by 0.5 inches tall.
After placing the field, right-click it and select Properties. In the General tab, give the field a descriptive name such as Applicant-Signature or Client-Signature. The field name identifies this specific signature in the form's data and should be unique within the document. In the Appearance tab, configure how the field looks when printed and when displayed on screen. In the Signed tab, choose what happens after the recipient signs: lock the document to prevent further changes, or allow continued editing.
Configuring the Signature Field for the Recipient's Experience
In the field's Properties dialog under the Signed tab, the option Mark as read-only after signing locks the document after the recipient applies their signature, preventing any further modifications to any form field. This setting is appropriate for final documents such as signed contracts where no changes should occur after signing. Leave this option unchecked for forms where the recipient may need to sign and then continue filling other fields, or where multiple signatures from different people are required.
Under the General tab, add a tooltip that appears when the recipient hovers over the signature field. A tooltip reading Click here to sign. You can type your name, draw your signature, or upload a signature image guides first-time users through the signing process and reduces confusion about what the field does.
Adding Signature Fields for Multiple Signers
For forms requiring signatures from multiple parties, a contract that needs both the client signature and the company representative signature, or an approval form that requires sign-off from a manager and a director, place a separate signature field for each signer. Name each field to identify the signer: Client-Signature, Manager-Approval, Director-Signature. Position each field near the corresponding name and title text on the form.
Some PDF signing workflows support sequential signing, where the document routes from one signer to the next automatically. Configure the signing order in the signature field properties or in the document's signing workflow settings. The first signer receives the document, signs their field, and the document automatically prompts them to forward it to the next signer. Sequential signing preserves the intended signing order, which has legal significance for some document types.
Testing the Signature Field Before Distribution
After placing and configuring all signature fields, save the form and open it in a standard PDF viewer such as Adobe Acrobat Reader, not the Pro editing version. This simulates the recipient's experience. Click each signature field and confirm it activates the signing process. Go through the signing workflow for each field and verify that the signature appears correctly, in the right position and at the right size.
Test the form on at least one mobile device if any recipients are likely to sign on a phone or tablet. Mobile PDF viewers handle signature fields differently than desktop viewers, and a field that works perfectly on desktop may be difficult to activate or may display incorrectly on mobile. Testing across platforms catches these issues before they frustrate recipients.
| Field Setting | Purpose | Recommendation |
|---|---|---|
| Field name | Identifies the signature in the form data | Use descriptive, unique names per signer |
| Tooltip text | Guides the recipient on how to sign | Add brief instructions for first-time users |
| Mark as read-only after signing | Locks document after signature is applied | Enable for final documents, disable for multi-signature forms |
| Signing order | Controls sequence of multiple signatures | Configure for documents where signing order matters |
Alternatives When a Digital Signature Field Is Not Supported
Some PDF viewers, particularly older versions and some mobile apps, do not fully support digital signature fields. For maximum compatibility, provide a fallback: include a visible signature line drawn on the page, a horizontal line with Signature: and Date: labels printed below it, in addition to the digital signature field. Recipients whose viewers support digital signatures can use the field. Recipients whose viewers do not can print, sign physically, and scan.