My grandmother passed away 5 yrs ago and there still is a mortgage on her house. I want to change the deed from her name to mine in order to sell the house. How do I go about this?

I'd start with the local Register of Deeds for you county and he/she can likely advise you of the process.

If you were not named in a will it might get a bit complex.

I rather suspect you will need a death certificate, for starters.