If you don't see all of the management options for your Google Group, it may have been created long ago and have old settings which prevent you from seeing the correct options. This is something you can fix yourself.
- Go to Group Settings for whichever group you need to repair. If you've forgotten how to access your group settings, it is described in this article: Manage Your Google Group Settings
- Make sure that the areas "add members","approve messages", "invite members", and modify members" all have Managers listed to the right or below of "Select groups of users"
- If you need to add managers to this list, please click on "Select Groups of Users" and select "managers" so that there is a check mark next to it.
- Save Changes.