Unless it was an older model with fixed chokes (M/F typically) it should have come with 3 choke tubes: IC, M, F, I think?
Then it depends what you are using it for. I used mine mostly for duck hunting and had to use steel shot, so I used the IC and Mod chokes.
If using lead on things like long range pheasant, or trap shooting then Mod & Full may be the better choice.
If for some reason the barrels are threaded for choke tubes but you don't have any... then you'll have to pick up some after-market tubes.
In any case, it helps to do a few test shots for patterning
