H1 and B1-B2 Visa

Here a issue and like to have some input for this. Mr.A lives in USA and doing his training on his H1 Visa. Then here Miss. B comes on a short course on Visa B1-B2. She landed in USA and week ago and she wants to marry to MR.A. If she marries with him. Can she adjust her legal status ? Can Mr. A apply for her to stay with him or not ? Or it is going to be difficult to adjust her status.

You mean, can she apply to adjust her status from B1/B2 to H4? She should be able to do so.