Can i use trigger ability's multiple times

It depends on the trigger — triggered abilities are by definition repeatable, but several things cap them.

Normally a triggered ability fires every time its condition is met (Rule 383), so if the condition genuinely happens twice, you get the effect twice. But watch these caps: abilities that say "once each turn" or "the first time…" only fire that many times (Rule 383.3.e), Attack and Defend triggers only fire once per combat even if the unit gains the designation again in that same combat (Rules 383.4.e.2.a / 383.4.f.2.a), and Conquer triggers need an actual Conquer — since each battlefield can only be scored once per turn, you can't re-conquer it to farm the trigger.

If you name the specific card, I can tell you exactly what its limit is.