In order for someone to participate in the phpBB forums, they have to register by clicking the register link.

where they create their username and password ...

There is a CAPTCHA to prevent robot registrations.

You can set up the forum so that an admin have to approve the registration before the user is allow to post. This is done by the following steps.

1. First login as admin to the administration control panel as described in another tutorial.

2. Under the "general tab", click on "User Registration Settings"...

3. You see that you have four options ...

a) "Disable" means that new users will not be able to register.

b) "None" means that no activation is required. That means once the user fills out the above user registration form, the user can immediately log in and post.

c) "By User" means that an confirmation email is sent to the user containing a link which the user must click on in order to activate the account and be allowed to post. This also ensures the correctness of the user's email.

d) "By admin" means the user will be informed that it requires Admin activation. The admin will be informed by email that a new user has registered and admin needs to activate account. The admin should follow the link in email to activate the user's account.

Alternatively, an admin can also activate user account, by ...
a. Go to Admin Control Panel
b. Click tab "Users and Groups"
c. Click link "Inactive user"
d. Checkmark the user that you want to activate.
e. Select droplist "Activate" and click "Submit" button next to it.
f. User will be informed by email that their account have been activated.

4. If admin want to create specific accounts for specific members instead of having the user create them for themselves, the admin can just click the register links to create the users.

5. Admin also have the power to change another users password, email, or to delete the user.
a. Go to Admin Control Panel
b. Click tab "Users and Groups"
c. Click "Manage Users"
d. Type username and find user.
c. Once you find the user, admin will see options to change their passwords, email, or even delete the user.

Note: this is based on version 3.0.5 of phpBB.