You can decide by yourself what kind of information about your customers you would like collect and if this information is mandatory in order to proceed with the payment.
If you go to "Pages -> Overview -> Edit -> Form fields" you have the option of setting which information you require from your customer. So you can determine yourself what fields the customer has to enter.
Click on New element to insert as many fields as you like and select the triangle pointing downwards for each field type to determine the type. Under Mandatory field, you can specify for each field type whether it is a mandatory entry or not.