Hello Amanda,

Thanks for reaching out to us. The default customer information fields are first name, last name, phone number, email. All other fields can be added with the custom field option. You can find more information about custom fields on this link.

You can also make the phone number and email fields mandatory. You will this option in General settings, and you also need to make sure that the mandatory field is configured in booking form settings. So, Customize / Step by Step v2 / Customer information / Options and you need to enable it there. 

I hope it helps. 

I was referring to this section -

When you open it, you see these booking forms

You need to select Step by Step v2 and then select the Customer Information step / Options