The Child

The Child is a 1977 American supernatural horror film directed by Robert Voskanian, and starring Laurel Barnett, Rosalie Cole, Frank Janson, and Richard Hanners. Set in the 1930s, it follows a young woman who takes a job as a nanny at a decrepit, isolated manor where a series of strange incidents begin to occur.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.