If you’re using a Blueprint for your character, and it’s based on character class, you can open up Blueprint and look in Components tab at top. If you then look over to left, there will be a My Blueprint section with several dark components listed, one of which will probably be FollowCamera:
This should be pretty similar for Third Person, First Person, and Top Down code templates. I think some of templates don’t have a camera hard-coded into character class, in which case you wouldn’t see one in Components list. If you don’t have a default camera in there (or you removed camera from character class via code, as mentioned above), then you can simply go to Add Component drop down and select a new Camera component, which should have Auto Exposure already accessible.
Hope that helps! Let me know if you have more questions.