State tax filing

The Toledo site only offers info on where to pay.  Where do we get the forms to complete the taxes at?  I obviously won't owe Toledo and they may owe me, but I don't see how to ever get that information.

 

Also, in general if I pay into Toledo city all year and I want to have the credit added to Michigan, what will that do to my Michigan return if I usually get a payment (not owe)?  Will this possibly raise the amount of return I get?  I've missed the last 4 years of this option, but I'm not going to try to amend other returns (and complete 2020) if it really isn't going to make a difference.  The amount I've paid in yearly for the last 4 years is between $1500-2000 to Toledo on returns that are usually between $500-1500.