How to read OTP (one time password) from File(Notepad/Excel) or how to read directly from email

How to read OTP (one time password) from File(Notepad) or how to read directly from email.

Hi
For our android app test i will need to use password that sent to a email account.

My app deliver messages to mail. but how to read message from gmail.

reading mobile messages as well as reading Gmails would be a solution.

Thank you all