My Mom wants to add me to her home title. She still has a mortgage on the house. Can she add me and if she does will it change anything? Does it cost to do this?

See this post:

https://www.askmehelpdesk.com/real-estate-law/how-add-someone-your-deed-91136.html

I think you mom might want to rethink this. As the link notes, she has to "sell" you a share of the property. Such a sale will have tax consequences. It would also need to get the approval of the mortgage lender because there is probsably a due on sale clause in the mortgage.

It may work out better to leave you the property in a will. Or to create a trust.