Personally I give each character a face, either from a person I know who matches their personality or a celebrity that fits the description, even though sometimes it can be really annoying if the author gives more details on the persons appearance and my character doesn’t fit that lol. I’m very curious as to what other people do.
i normally fully visualise characters on my head– i don’t base their appearance on faces that exist in my memory, they’re all an extension of my own imagination.