Not everyone can golf, but they may still want to support the cause. Add a Call-to-action block on your event page set to Donate. When card payments open, it opens a simple donation page where anyone can give any amount by card.
Donations are always free — Redswing takes no fee on donations. Card payments are not open yet; until then, record gifts by check or cash. Donations count toward your fundraising total and donors get an automatic thank-you (and a tax receipt if you've set up your tax info).
The live fundraising meter on your leaderboard shows the total. The donate prompt after scoring takes gifts only once card payments open, and players' own peer-to-peer pages are on hold.