What is MgCl + H2SO4 yield MgSO4 + HCl

I think you are having trouble because magnesium chloride is MgCl2.
That should make it easier to balance :)

MgCl2 + H2SO4 -----> MgSO4 + 2HCl
Metal first
SO4 polyatomic the same on both sides (they stand alone) you must have the same coefficients for each SO4 compound in equation.

I hope it helped