If you want to customize the fields you want for the Booking Request Form or the Questionnaire, please follow these guidelines. You just need to go to:
Settings - Booking - Request Settings
Then you can pick which fields you want in either the request form or the questionnaire OR both, and which of them should be 'mandatory' for the promoter.
If you want to create a personal custom field, you can just add it on the proper section clicking on the '+ Add ' button.