You are the direct and sole beneficiary of the payments you receive. If a student of yours requests a receipt for his/her payments, you should consider providing one. It is vital that you could create a trusting rapport with your clients. Students may suggest that they only pay for one or two lessons first before perhaps agreeing to make batch payments. Tutor punctuality and helpfulness will improve your chances of acquiring long term students. However for extra confidence building, students may request a written confirmation of their payments. You could send such confirmations via email or any other method of communication that students prefer.