Without a 3rd party server for the payments u would need to either install a ready built client for crypto payments or u build it from scratch with your own crypto wallets and multiple json rpc connections to it. Than connect this to a database and keep track of the payments by looping over the tx’ids / addresses. Once confirmed send an email with PHPmailer or any other packages available. I have made such systems before, if u need help I can set this up for u.