Record a deposit on an appointment
Open the appointment and tap Record deposit.
Enter the amount under Add deposit amount. Received so far shows what is already logged against that booking.
Use the note field for how it actually arrived, for example paid via Venmo on the 15th. Six months later that note is the difference between a clean set of books and a guess.
This is for money that came in outside the app. Money taken through Collect payment already records itself.