From what I understand, it’s a platform where you can create games and monetize them by doing things like adding subscriptions, item or ability shops, add access fees, etcetera, that require real world money to be exchanged for them. Though, I think it could also be robux, but I wouldn’t know because I avoid that service like the plague.

There’s a whole entire webpage dedicated to this monetization thing that’s out in the open, if you wanna read it.