account upgrade

Hello, I would like to ask how you made the Upgrade VIP page. I have xenforno too but i am new user so i not so good in that. I mean this page - https://enxf.net/account/upgrades . What for is that addon and some tutorial how to set it up please

What is the account upgrade xf addon? that can be upgraded to a VIP user group by paying. I created a new vip user group. What xf addon can I use to upgrade to this vip user group?