How to Enable self-registration as a Teacher and student Moodle?

 1- i want to allow new users to chose the account type : (Teacher or Student), but must be validated from admin or manager.

how can i do that ?

i don't want to make that change for every one in admin area

2- is there any video conference and whiteboard that can work with moodle mobile client?

3- how to allow teacher create courses from mobile app without logging to website?

thank you very much