when opponent charms my azir sovereign to a battlefield which he has units, can azir sovereign's text trigger ? "When i attack, you may move any nubmer of your token units to this battlefield.

Yes. If the opponent's Charm moves your Azir, Sovereign into a battlefield they control with their units (and that battlefield isn't already Contested), your Azir applies Contested — not the Charm caster — so you are designated the Attacker and the opponent becomes the Defender.

Once Azir gains the Attacker designation, his "When I attack" trigger fires (Rules 383.4.e, 459.2.b). "You" in the ability refers to you as Azir's controller, so you may move any number of your token units to "this battlefield" — Azir's current battlefield — regardless of who played the Charm.

Caveat: if that battlefield were already Contested (combat/showdown already in progress there), the arriving Azir would instead be a Defender and his attack trigger would not fire.