Custom Fields in WP Full Pay Forms

Custom fields let you collect additional information from customers during checkout. This article explains which field types are available, how checkbox-style inputs work, and how to use the Terms of Service checkbox as a workaround for use cases like GiftAid opt-in.

Available Custom Field Types

WP Full Pay supports text input custom fields only. You can add up to 10 custom text fields per form.

To add custom fields to a form:

1. Open WP Full Pay → Forms and select the form you want to edit.
2. Go to the Form Fields section of the form editor.
3. Under Custom fields, click Add field and enter a label for each field.
4. Optionally set Make custom fields required? to "Yes" to prevent submission without a response.
5. Save the form.

📝 Note: Checkbox-type custom fields are not available. If you need a checkbox — for example, a GiftAid opt-in on a donation form — see the workaround below.

Custom field values are stored with the transaction as Stripe metadata. See Custom Fields as Metadata for details.

Workaround for Checkboxes (e.g., GiftAid)

WP Full Pay includes a built-in Terms of Service checkbox that you can repurpose for any checkbox opt-in — such as a GiftAid declaration on a donation form.

When enabled, this checkbox appears on the form and must be checked by the customer before they can submit. Its label text is fully customisable.

How to set up the Terms of Service checkbox as a GiftAid opt-in

1. Open WP Full Pay → Forms and select your donation form.

2. Go to the Form Fields section of the form editor.

3. Enable the Terms of Service checkbox option.

4. In the Terms of service label field, replace the default text with your custom opt-in message. For example:

   I am a UK taxpayer and I authorise the charity to reclaim Gift Aid on this donation.

   You can include an HTML link if you need to point to a policy page.

5. Set a Terms of service error message so customers see a clear prompt if they try to submit without checking the box.

6. Save the form.

⚠️ Important: The Terms of Service checkbox only records whether the customer agreed at the time of payment. It does not automatically process GiftAid claims or submit data to HMRC. You will need to handle GiftAid processing manually or use a third-party automation tool (such as Zapier) to forward the opt-in data to your chosen workflow.

Relabelling the checkbox via translations

If you want the checkbox label to appear differently across forms, or if you need to change it without editing individual forms, you can override the default label using the plugin's translation system.

Testing the checkbox in sandbox mode

Before going live, switch the plugin to test API mode (WP Full Pay → Settings → Stripe account) and submit a test donation to confirm the checkbox appears and that the opt-in value is recorded correctly in the Stripe metadata.

Custom Fields as Metadata

All custom field values — including the Terms of Service checkbox state — are stored as Stripe metadata on the transaction.

Where you find metadata depends on the form type:

• Donation and one-time payment forms: metadata is on the Stripe charge (visible in Stripe Dashboard → Payments).
• Subscription forms: metadata is on the Stripe subscription (visible in Stripe Dashboard → Customers → Subscriptions).
• Save card forms: metadata is on the Stripe customer (visible in Stripe Dashboard → Customers).

For step-by-step screenshots of each location, see Where are custom fields on the Stripe dashboard?

If you need to attach metadata that comes from URL parameters rather than form fields, see Adding custom metadata to payments.