What can I do to transfer ownership of a house that is owned by my greatgrandfather who died in 1975 and my grandfather lived in since 1964 who recently passed away.

If you are the heir, as part of the probate process, the house should have been deeded by the estate to you. Typically, the estate will deed the property like a house to the heir, with the estate administrator signing for the estate.

who lives in a home that was not paid for because of a death the one paying for the new home if it was not paid for or someone else

who lives in a home that was not paid for because of a death the one paying for the new home if it was not paid for or someone else the mortgage company only cares if it is paid for not who lives in it but no will was left