If you wish for DOB to be a mandatory field for guest signup, you will need to submit a request to Punchh. This function can only be set up by Punchh admins as clients do not have access to the applicable section of the Punchh Platform.
If you need this function enabled for your business please submit a ticket to support@punchh.com via email or through the normal channels using the support portal accessed directly from the platform.