After the customers book your service, they have two options to pay.

The easiest is by online payment. This allows a seamless experience for your customers. This also allows you as a professional not to have to deal with money. You can set a standard fee, thereby avoiding requests for discounts and other money issues. Learn more here with Booking payment options

Once a customer books an instant booking confirmation, the customer will only need to enter payment details. That's it!  

Their recourse is when you want to approve a booking first before payment. Upon your booking approval, the customer will receive an email with a link to pay.