This is the woman. We borrowed the car from her. (formal)
This is the woman from whom we borrowed the car.
We watched a movie last week. The audience complained about the movie a lot.
The movie, which we watched last week, was complained about a lot by the audience.
Brenda is a friend. I went on holiday with her. (2 ways)
Brenda is a friend with whom I went on holiday. / Branda is a friend who I went on holiday with.