If both my wife and I are on the paper work for a new vehicle tags, do we both have to go to the BMV?

Yes or have a power of attorney.

i think u both do have to go to the BMV

It depends on the wording on your title. If it says "and" yes you both have to agree but they have a form the other person can sign that provides power of attorney for just that purpose and one time only. If it says "or" it can be either one of you.