Slitherine

Hi
I have seen in a multiplayer game that at one point, one the units of my opponent before attacking had the wors "charge" getting out of it (It was a phalanx unit). I wonder how can I charge with a unit and what is the benefit, I didn´t see that in the manual

It is an automatic move - i.e. not under the AI or player control. There is no advantage to it.