Help in drawing resonance structures in case of polybasic acids While drawing resonance structure of dibasic or tribasic acid, e.g. should I take out two $\ce{H+}$ (in dibasic) or three $\ce{H+}$ (in tribasic) together or one by while drawing resonance structure?

Do dibasic acids give both $\ce{H+}$ at once or one by one?

Actually, I was drawing resonance structure of $\ce{H3PO4},$ but got confused. Should I remove all three protons at once or only one?
It depends on what specifically the question is asking you to do.

In reality, a polyprotic acid such as $\ce{H3PO4}$ becomes deprotonated in a sequential way; the first proton is the easiest to remove (most acidic), then the second, then finally the third is hardest to remove (least acidic).

So there are four different species that the question might be asking you about: $\ce{H3PO4}$, $\ce{H2PO4-}$, $\ce{HPO4^2-}$, and $\ce{PO4^3-}$

Each of the three anionic species above has multiple resonance structures.