1. Only those who are given a DeathNote by an administrator have a DeathNote. Thus, the administrator decides how many DeathNotes are in circulation, who has them, and who those DeathNotes will pass on to if/when the current holder dies or loses possession of their DeathNote.
2. Anyone who doesn't have a DeathNote is a normal person. There are no psychics, no people who can magically see shinigami or weild supernatural powers. You are a normal person.
3. Posts should be at least a paragraph unless there is so little leading up to it (as per conversational exchanges) that it is not feasably possible. As this is DeathNote, that should be a very rare occurence.