Alright, so let's talk the different forms you may have heard about.
In Kingdom Hearts 2, Sora gets the Drive Forms. There's the physical Valor Form, the magic Wisdom Form, a combination of the two in Master Form, and the powerful Final Form.
In other words, Ultraman Orb and Geed. Aside from those, there's the AntiForm that acts as a punishment for abusing the forms too much, and the remaster adds in Limit Form, which acts as a callback to the original game.
In Kingdom Hearts 3, we instead have Formchange, which is much more detailed and complex. Instead of just altering your stats, they also change the Keyblade into something else entirely. There's Second Form, which references KH2, the defensive Guardian Form, the physical Strike Form, the long-range Element Form, and the speedy Blitz Form. There's also Rage Form, which is a critical-health desperation thing.
There's also a couple unique forms; Light Form and Darkness Form, triggered by one of Roxas' Keyblades, Double Form, which uses both, and Ultimate Form, which is accessed through the Ultima Weapon.
For further reading, I direct you to
here and
here. If we need to adapt a form-switching thing into a moveset, I think the Drive Forms would be much easier than the Formchanges.