Yes, anything that is not your original thought should be cited, regardless of the origin of that information! The only exception is for common knowledge: saying that the Earth orbits the sun, for instance, does not need a citation from your astronomy textbook. What's considered "common" knowledge depends on the audience you're writing for, so check with your professor about what you can safely assume.
Most textbook citations will follow a citation template for a book with authors or an edited book. If there's a section by a different author than someone named on the cover (like a story or article reprinted in the book), use a template for a work in an anthology.
