I would like to purchase my sister's property

[Rey Alvarado]

I hope this is the right area to post this but I am interested in purchasing my sister's property (which is currently rented). Here is a little backstory.

She lives in New Jersey but purchased the property here in P.A years ago and used me as the property owner. On paper the property is mine, but in reality its hers. I just collect rent and make deposits. She did it this way because it is cheaper here and she really doesn't want to live in P.A.

My question is, what is the best way to approach her with a deal? Should i offer her the money she gave down and ill take over the mortgage payments?

Thank you