Browse users will display a complete list of the users registered on your forum.
Find users will allow you to search amongst registered users, using various criteria.
The Create New User tab will allow you to create a new registered user for your forum. You should always double check and make sure you are adding it to the appropriate user group with the corresponding permissions for the person that will use the username.
Merge Users will allow you to merge two user accounts into one. The “Source Account” will be merged into the “Destination Account” leaving only the destination account. The source accounts posts, threads, private messages, calendar events, post count and buddy list will be merged with the destination account. This could be particularly helpful in case a user has forgotten his account at some point and started using a new one after that. You should always bear in mind that such merge cannot be undone.
Via Manage User Groups you can alter all user groups that are currently setup on your MyBB forum. In addition, for staff groups such as moderators and administrators, their display order on the forum team page can be managed.
Clicking Options -> Edit group will open the control panel of the group where you will have full control over the various options for the chosen group.
Bear in mind that the options we have just set are just sample and it is not recommended to make such modifications for the general registered users group.
If you need to add a custom user group with specific permissions, this can be done via the Add New User Group tab. For the ease of use you will be allowed to copy the permissions of an existing user group and then further adjust the settings via Manage User Groups.
The user titles option does not have any formal significance. User titles are set in order to distinguish the users with high post count that are contributing more to your forum from the newly registered. The exact post count and titles are absolutely up to you. You are not obliged to keep the default ones.
This was explained under Configuration -> Banning section.
Via Admin Permissions you can manage the administrator permissions for individual users. This will allow you to lock certain administrators out of different areas of the admin control panel.
The Mass Mail functionality allows you to sent messages to multiple users for your forum. Note that it is not imperative those messages to be sent as emails, you can also post them as personal messages at the forum itself.
The Mass Mail Queue will show you the current messages that are queued for delivery. Note that the email delivery will run according to your settings under Tools for your MyBB installation. If you would like to force the delivery this can also be done via Tools -> Task Manager -> Clicking the Clock button for Mass Mail.
The User Promotion will allow you to automatically assign new group for registered users that meet certain criteria. Here is an example how to setup automatic promotion from registered to moderator based on posts count and total time registered on the forum: