This page is going to go over the rather basic Invite Macro. You only need to make this macro on one character and that will most likely be your tank. Really, all the macro does is invite all of your characters to a group - it's as simple as that! The reason I'm telling you to make this macro is because you can't imagine the amount of time it saves to do something as simple as this.
I log into the game each day and I hit F3 which is the key my Invite Macro is bound to. Then I turn on Isboxer Broadcasting and type out /inv and wham all my characters are in a group just like that. If I am raiding I just have to type out a few /raidinvites to invite group leaders and that's it!