How to send an invite to a facebook group?
The problem: In a perfect world, there would have been two options: Add and Invite. But Facebook has this annoying pattern, of providing only one option. In this context - that of ADDING people to a group. The outcome? Ann innocent group admin adds a Facebook friend, wishing him/her involved in this certain activity, and instead of gratitude or joy, that poor admin gets a protest - why did you add me ? I want to make up my mind alone about which group I'm member of...
The solution: Instead of using the Facebook friend name, add that person via his/hers EMAIL. Then Facebook sends them an Invite.
How to make a group member into an admin or a moderator?
Go to the members list. Near each member there is a small cog-wheel icon, a near universal symbol, nowadays, for the settings. Click that, and one of the options is to make that member into an admin or a moderator.
What is the difference between a moderator and the admin?
The admin can do everything about the group,the members and about the contents - the messages. The moderator can handle members and contents. On the following link, you can see a nice table Facebook prepared detailing the difference.
(some may find this intuitive, but as the person who asked obviously did not, it seems worthwhile to document)
A group is deleted once it no longer has members. Using the members list, use each member's setting to remove that member from the group. Once you are the last member of that group, select "Leave Group" near your name.
BTW, according to Facebook, "Admins can't delete a group they didn't create unless the original creator chooses to leave it." Remember that if you are an admin, instead of deleting a group, you can Archive it.