You use wherever to indicate that something happens or is true in any place or situation.
e.g. Some people enjoy themselves wherever they are...
e.g. Jack believed in finding happiness wherever possible...
You use wherever when you indicate that you do not know where a person or place is.
e.g. I'd like to leave as soon as possible and join my children, wherever they are...
e.g. 'Till we meet again, wherever that is,' said the chairman.
You use wherever in questions as an emphatic form of 'where', usually when you are surprised about something.
e.g. Wherever did you get that idea?...
e.g. Wherever have you been?
You use or wherever to say that something might happen in a place other than the place you have mentioned, but that you are not able to say exactly where.
e.g. The next day she was gone to Lusaka, Kampala, or wherever.
e.g. ...language which will allow the students in class or wherever to express their opinions.