send a letter to the lender giving permission for your wife to access the account. If you want to get credit for the loan, add her to the checking account where the mortgage payment is being made and she can show proof of making the payments on time. it doesn't necessarily have to be on the credit report, afterall there are mortgage companies who don't report to the credit bureaus.

Tom is right. Not really sure why you would want to do that. You are just tying up her credit. If you are trying to establish credit for her there are other ways to do it that is less costly.

I have seen this asked many times.
No way to add her. You would need a refinance.
You can add her to the deed, is that not good enough?