Is there a setting the administrator can set . So that before someone can post a message it will need to be approve ?
yes
https://wiki.simplemachines.org/smf/SMF2.0:Permissions#Topics
Quote
Post new topics, without requiring approval - Determines whether users in this membergroup can post new topics without moderator or administrator approval.
Post new topics, but hide until approved - Determines whether users in this member group can post new topics which are visible to moderators with the necessary permissions or administrators, but not other users.
Post replies to topics, but hide until approved - Determines whether users in this membergroup can post replies which are visible to moderators with the necessary permissions or administrators, but not other users.
Post replies to topics, without requiring approval - Determines whether users in this membergroup can post replies without moderator or administrator approval.
Post attachments, but hide until approved - Determines whether users in this membergroup can post attachments which are visible to moderators with the necessary permissions or administrators, but not other users.
Post attachments, without requiring approval - Determines whether users in this membergroup can post attachments without moderator or administrator approval.