People often ask where they can find their TOEFL Registration Number. This is usually because the school they are applying to has asked for it.
Sadly, there is no TOEFL Registration Number. It doesn’t exist.
The schools are probably asking for your TOEFL appointment number. To find it you should log in to your TOEFL account and then click on “My Scores.” Then click on “View Scores.” Your appointment number will be displayed below you name, like in the screenshot:
It is also found in your PDF score report, and in your paper score report, if you’ve got on.