Subject to deal off market purchase

Hello BP family i have an off market deal a property belongs to my aunt. She currently has rented out. And is tired of having this property. She offered it to me and is asking i take over the payments (i will cash out refi at a later date after seasoning period) i know i have the option for “ “subject to” deal however am very new to this. My question what type of paperwork i need to transfer title protecting me and her? Also i heard somone mention i need also “limited power of attorney” papers on file as well. Any input would be much appreciated or if i can be sent to the right person to talk to for help is very much aprreciated. Property is in arlington Texas