Is it possible to prevent a new registered user from accessing the forums, and can only access it when I activate it? The activation will only occur when the administrator verifies the information of the
new registered user.
Thank you for your interest in wpForo.
You can set different Forum Accesses to different Usergroups. Each forum can be available for certain Usergroup. There are many examples explained how to manage Users accesses in Forums:
Recommendations for user approved feature can be found under the "approve user" tag.