Custom Fields are custom questions you can add to your Harness checkouts (fundraising pages) to acquire information from your donor beyond the traditional/default fields/data points (ex: name, email, address, phone number, etc. - see the full list of the donor information we collect & your fundraising page customization options).
Here are a few examples of some common custom field questions:
What's your preferred T-Shirt size? (Select)
What location would you like to designate your gift to? (Select)
How did you hear about us? (Select/Text)
Would you like to be added to our emailing list? (Checkbox)