Step One: Create a Processing Fee Designation.
Under the Designation tab, click on Add in the Designation Folder box.
Next give your designation a name, such as Processing Fee, summary, and description. Put a check in the box, “Include on Tax Receipts” and uncheck “Include in Catalog”. Save your changes at the bottom of the page.
Step Two: Turn on Donor Assist
First hover your mouse over the Gear icon in the upper right-hand corner and click on Settings.
Next in the middle of the page under Donor Covers Transaction put a check in the box next to “Allow the donor to cover the cost of transaction.” Then choose your Processing Fee designation from the Designation drop down box. Then save your changes at the bottom of the page.
Now when Donors give a donation with a credit card, they can choose to cover the cost of the processing fee.