Please tell me the answer to what is the title of the movie in the 80s that is about a robot grandma

Are you thinking of THE ELECTRIC GRANDMOTHER?
It was a TV movie from 1981, based on a short story from the great Ray Bradbury. It was about a lone father and his three children and a robot grandmother and she could do things such as produce hot chocolate from her finger and produce yards and yards of string from herself.

The original short story by Ray Bradbury was, "I Sing the Body Electric," which appeared in the collection of stories of the same name.

I think the movie you are looking for is called The Electric Grandmother. Hope that helps!