How do I add my wife's name to my mobile home title? How do I get the bank off the current title?

It depends on whether your type of title is registered at the DMV or the city/town/county deed office.

You have 3 questions here. Losing the title to a DMV home is more trouble.
Contact the bank first. When someone pays the last payment on a loan, the lender discharges the lien to the agency that keeps the deeds/titles.

Adding your wife is the least of your worries, behind the first two.