Signature Field

> System field: Fundations (free). Admin management, export, bulk delete: Fundations Pro.

The signature field lets donors draw a digital signature during checkout. The signature is saved as an image attachment and linked to the donation record. Fundations Pro adds the admin tools for viewing, downloading, and managing signature images.

Why use this

Some fundraising contexts, particularly charity events, legal pledges, or campaigns that require participant acknowledgment, need a record of the donor’s agreement at the time of donation. The signature field captures this directly in the donation form without requiring a separate document signing workflow.

What it does

On the donation form (free)

Adding the system:signature field to a form template renders a signature pad on the donation form. The donor draws their signature with a mouse or touch input. On submission, the signature is saved as a PNG image attachment in the WordPress media library and linked to the donation record via custom_fields['signature_attachment_id'].

In the admin (Pro)

Fundations Pro extends the admin with several signature tools:

Feature	Details
Signature preview	The signature image is displayed in the custom fields section when viewing a donation in the WordPress admin.
Media library filter	A “Fundations Signatures” filter in the media library shows only signature images.
Bulk delete per template	Remove all signature images associated with a specific form template at once.
ZIP export per template	Download all signatures for a form template as a ZIP file. Requires PHP ZipArchive.
Automatic cleanup on deletion	Deleting a donation removes its linked signature attachment. Deleting a signature attachment from the media library clears the reference on the donation record.

How to use it

Adding the signature field to a form

1. Go to Fundations → Forms.
2. Open the template you want to edit.
3. Drag the Signature system field into the form layout.
4. Save the template.

Viewing a signature

1. Go to Fundations → Donations and open a donation that used a form with the signature field.
2. The signature image appears in the custom fields section below the standard donation details.

Exporting signatures as a ZIP

1. Go to Fundations → Forms.
2. Open the template whose signatures you want to export.
3. Click Export Signatures as ZIP.
4. The ZIP file downloads immediately.

Each image in the ZIP is named after the donation ID.

Bulk deleting signatures

1. Go to Fundations → Forms.
2. Open the template whose signatures you want to delete.
3. Click Delete All Signatures.
4. Confirm the action in the dialog.

This removes signature images from the media library and clears the references from donation records. It cannot be undone.

Filtering the media library

1. Go to Media → Library.
2. Use the Fundations Signatures filter in the filter bar.
3. Only signature images are shown.

Settings & options

There are no configurable options for the signature field beyond including or excluding it from a form template.

What you can and cannot do

• You can add the signature field to any form template.
• You can have the signature field in multiple templates independently.
• You can export all signatures for a template as a ZIP.
• You can bulk-delete all signatures for a template.
• You cannot re-sign a submitted donation. The signature is captured at submission time only.
• You cannot set a minimum stroke length or validate the signature quality.
• ZIP export requires PHP ZipArchive. If not available on your server, the export button will not work. Contact your host to enable ZipArchive.
• Bulk delete is irreversible.

Troubleshooting

The signature pad does not appear on the form. Confirm the system:signature field is in the active form template and the form block on the page is using that template. Check for JavaScript errors in the browser console that might prevent the signature pad from initializing.

The signature is not visible in the donation detail view. This requires Fundations Pro. In the free plugin, the signature is stored but not displayed in the admin. Activate Pro and confirm the license is valid.

ZIP export fails or downloads an empty file. Check that PHP ZipArchive is available on your server (class_exists('ZipArchive') should return true). If it is not available, contact your host or use the media library filter to download signatures manually.

Signature images appear in the general media library. Use the Fundations Signatures media library filter to isolate them. If you want to prevent them from appearing in content searches, the signatures have a _fundations_signature meta key set to '1' that you can use to exclude them in custom queries.

Developer reference

Attachment metadata keys

Meta key	Value	Description
_fundations_signature	'1'	Marks this attachment as a signature image
_fundations_signature_donation	integer	Donation post ID this signature belongs to
_fundations_signature_template	string	Form template slug/ID

Donation custom_fields key

The signature is stored in the donation’s custom fields as:

$custom_fields['signature_attachment_id'] = (int) $attachment_id;

Admin display hook

// Fires after custom fields are displayed in the donation detail view
// Use to add content after the signature image in the donation admin
add_action( 'get_fund_donation_detail_after_custom_fields', function( $donation ) {
    // $donation is the donation data object/array
}, 10, 1 );

AJAX actions (Pro, require manage_options)

Action	Description
get_fund_bulk_delete_signatures	Delete all signatures for a template. Accepts: template_id
get_fund_export_signatures_zip	Stream ZIP download. Accepts: template_id

Both require the get_fund_signature_actions nonce.