Air only blow out of my defrost vents and sometimes the floor but not out of the dash vents. it still blows cold air though. how do i fix this

A vent flap actuator probably needs to be replaced. It's what moves your vent flaps from heat to A/C or to plain "vent air" when you change settings.

The discussion in the link includes vent flap actuators. Unfortunately, they also include the infamous no low speed fan problem too.

Cannot get any air from dash vents while defrost and floor vents work fine...

Your particular actuator will be a different one than they found.
They're all a absolute pain to get at because they can be well buried in the dash. I would start looking under the dash on the passenger side, that's where most of the air control is. Cannot get any air from dash vents while defrost and floor vents work fine...

I think your problem is the head unit that selects where the air comes out ie. Face, floor, defrost, or hi-level face and floor. If that's not working then it will not let you switch location that you want the air to come out.

Under the dash there is a vacuum control that opens and closes the doors. Door could be stuck

Often a sign of a blend door problem. The blend door or doors are in the heater a/c box behind the dash.

the switch where you turn it to blowing at your head is probably out. you will need to replace the switch control where your defrost, foot, head etc. what make, model, year is your vehicle?

Check for vacuum hose leak.

Is it a new vehicle? I had a new vehicle that had the same problem. Answer was that the holes weren't punched out of the vent.

Sounds like you have a supply vacuum problem. When you lose supply vacuum to the control head it defaults to defrost.

common problem, check under dash by the gas pedal if control arms are muving went selecting from ac to heat cuz this it is the control for the vents to go from ac to heat and to defrost.

Had the same problem. believe it or not i changed the gas cap and got heat all around. something about pressure.