WHAT IS THE ERROR percentage between quasi static and full ?

Give more details please.

i mean if i have the same structure simulated using hfss and q3d what is the error between the s matrix from both ?

Depends on how the frequency relates to the geometry. Dimensions larger than lambda will give significantly different error from dimensions smaller than lambda. The error will depend on the individual problem I would guess.

I haven't used q3d, but this is the general principle.