If you wish to control how your members auto activate their account when they first sign up, you can do the following steps:
1. Go to Settings -> Advanced Settings
2. Search for auto-activate
3. You should get the following results:
A value of 1 will auto-activate the member when they sign up to your site. A value of 0 will request an email before activating the account.
By Default, PAID members get automatic activation while FREE members do not.
Now if you wish to make sure that, even with the Email, they are not activated, for cases where you would like to control the manual activation as an administrator, you can edit the Bootstrap Theme - Account - Signup Actions widget and add a check that looks for the auto_activate_free_members or auto_activate_paid_members so that the status for them is set to inactive. If you also wish to change the text shown to members when they sign up, you can edit the Bootstrap Theme - Success Page - Free Member Sign Up or the Bootstrap Theme - Success Page - Paid Member Sign Up.