Can your wife transfer her tag to my car?

She could in some states. However, since neither of us knows you, and you are not related to us in some way, then no. My wife will not transfer the tag from her vehicle to your car.

Seriously, your wife can transfer the tag from her vehicle to your car. Most of the US states are common property states. That is what you own in the marriage, she does. Even in states that are not common property states, the spousal relationship permits a lot of cross over of property.