H backs are the new age full back. H backs are used for more than iso blocking on a linebacker or getting trap hand off from the "I" formation. H backs are versatile weapons in your offense because they are both running back and wide receiver. I like to move my H back all over the formation, from split back, sniffer, slot/wing, both RBs on the same side of the QB (GoGo Style) and H beside QB with RB in the pistol. There are very simple tags we attach to our formations to tell the H where to align. By moving your H around you can create numbers, angles or match up advantages for your offense.
There are easy words that we use to tell the H where to go. These words are "strong and weak, close and away, near and far, will and mary". Once an H back understands these tags he can line up in 8 different backfield positions while the other players are aligned in base formations. This makes it look to the defense like we run a ton of different formations but really there are a few formations with the H moved to different positions in the backfield.