Where i can get invite to bittrex exchange for register new account?
You don't get an invite, you need to send a request try this link
https://support.bittrex.com/hc/en-us/requests/new?ticket_form_id=114093958552Choose Corporate and New Account Requests. However, sending a request doesnt guarantee you an account in Bittrex, it will only put you in the waiting list to be served by Bittrex. They call it a "waitlist form".