Grinder in metal or machine shop?

is there a grinder in the metal shop? I need to grind down some steel angle, the actual shape of it wont work in the miter saw.

Yes, there are a few

Do they require any training or can I just use them?

There is a belt grinder but you should bring your own 2x60 belts, might luckout but best to bring your own.
The bench grinders are for sharpening and generally in poor condition due to inexperienced people abusing them.
We have several angle grinders, bring your own 5/8-11 hard wheels or flap wheels.
There is a hot process safety class on that you should take before using the grinders.