What do marks mean?

[Punisher Magician]

In the R/S/E series what do the "Marks" mean like the square, circle, heart, and triangle? What do they do?

[Absol]

Theyre whatever you make of them. Like if you have several different teams, you can mark them all with the same markings, so you dont get confused...

[Rare_Pokemon]

yeah its something i never really utilized