Which of the following sentences is more used by English native speakers verbally and in writing?
- Do you know where Susan works?
- Do you know, Where does Susan work?
Number 1 is most used in verbal and writing.
Number 2 is not really a good/correct sentence. I could see a sentence like that being said in verbal communication, but not written. For example, someone could say Do you know then pause for a while like they are thinking about something, and then say Where does Susan work?. But it would still be more appropriate to say where Susan works.