Go to the sign on page: https://www.italki.com/signin and select " forgot your password?" at the bottom. It will give you the option to change your password.

Click on you Icon then click "account setting" then clock the "pencil Icon' to change you password. It might differ on the app con compared with a desktop or mobile phone. If you forget and cannot log in. There should be an option to reset your password whenever you get an error message. This is standard on any internet account.