Explanatory text for donor-covered fees

Open Online Giving → Campaigns or Online Giving → Forms, select the campaign or form, then go to Giving Experience → Form Settings & Display → Display. Choose the relevant Pre-Payment Form, Payment Form, or Post-Payment Form settings; older interfaces show those as separate tabs.

The fee settings enable the option and control its default state; they do not provide a custom-copy field for the checkout checkbox sentence. That sentence is fixed in the checkout template with a calculated amount. Put explanatory wording in the payment-stage Form Text under Form Settings & Display, then preview it. This edits nearby form copy, not the checkbox label itself.