A class at Hogwarts about the study of muggles. Hermione Granger took this class in her third year. Probably the first muggle-born ever to take the class. ("But it'll be fascinating to study them from the wizarding point of view," said Hermione earnestly.)
They probably don't give instructions on how to use muggle-tech, just more general stuff. (That is to say, they won't teach you how to use a telephone, but they'll tell you what one is.)

The Harry Potter Project