Which of these acids has more equivalence points in its titration curve? "H"_2"SO"_4 or "H"_3"PO"_4? How can you tell which one is the weaker acid?

Not all acids ionize or dissociate in the same way and produce the same concentration of ${H}^{+}$. There is some difference.
The one that produces more equivalence points for the titration is ${\text{H"_3"PO}}_{4}$. One can obtain from the first half-equivalence point the $p {K}_{a}$ of each acid + compare.