When you create a customer in Appointedd, whether when you're making a booking or in the customers tab, you need to enter their first name and last name.
Now, to ensure that you take all of the information necessary, you have the option to make the email address and phone number fields mandatory also.
To do so, just go to CRM under the your business tab and find general fields.
You can also create your own custom fields which you can make optional or mandatory as required. Find more about custom fields in our support base.