Taking a deposit for work that is to be carried out in the future is quite simple.
In the account tab in the patient’s record, click on Take Payment and enter the payment details.
As there will be no invoice to explain this payment against, you can just enter a note in the payment screen and the payment will show as explained and the note will be displayed where the explanation would usually be. The patient’s balance will be credited accordingly.
Once the work has been carried out and the invoice raised, you can delete the payment explanation and point the payment to the invoice instead.