What formatting is required for phone numbers on the booking form?
When you add the question type Phone Number to your booking form, YouCanBook.me will automatically detect the location of the people booking with you so there isn't any special formatting required.
When the booker sees the Phone Number question on the booking form, it will already include the flag of the country they are in:
The flag takes care of the country code for the booker. They just need to enter the phone number as they normally would. No special formatting is required.
The location detection is based on the booker's IP address. If it isn't correct, they can select the correct country from the dropdown next to the flag and enter their number as usual.