To set up online booking fee, you can do by two ways:

Fixed online booking fee

1. Administration

2. Appointment type

3.

4. Select booking fee strategy as fixed, and input your booking fee 

5. After finish the online booking process, the stripe page will show the fixed booking fee

Assessment

1. Administration

2. Appointment type

3.

4. Choose the associated assessment you created

5. Choose booking fee strategy as assessment

6. In  your assessment template,  a select box field, called booking_fee must be present in it. (select amount in the value field, can't be negative)

7. Follow the process of online booking, and the stripe payment will be showing what is under the assessment.