Can I take over my mother's mortgage?

My mother wants to sell her house to me. She can't keep up the day to day up keep of a house anymore and would like to instead live in the in-law apartment that is attached to the home. Can she simply write her mortgage over to me? Will me husband and I then be able to own the home and continue her mortgage as our own? How does this work? What are my options? Do we have to apply for a new mortgage ourselves? Thank you!