I found the way but it is not very good solution if you have lots of members.
I installed a plugin so that no user can activate their account until I activate it by myself.
So that when someone paid then I go back end of site and activate the user. A user cannot access the site without my activation.
But this isn’t the correct way. There must be another way.
This site has a good activation process but not sure what plugins they use.
https://www.appthemes.com/
