If you need to update your username or the email address you use on your Rakuten TV account, the first thing you have to do is go to our webpage https://rakuten.tv/ and enter with your existent email and password.
After you log in, you have to go the upper right corner of the web page, to unfold the menu of your account, and click on the option "Settings".
Inside the Settings menu you will find 4 tabs. In the first one, Profile, you will have the option to change your Email and Username, add your Telephone number and update your existent Password. Remember to click on the yellow button "Proceed" after updating the necessary information.