You can easily change your password if you forgot it or want to change it. There are two different process to follow depending on your precise situation:
If you still have access to the app and are logged in, If you forgot or want to change your password, you need to visit the Settings and click on the Password tab. There you simply need to write a new password and save it. The system might ask you to log out and log back in with your old password in order to ensure it is you before letting you change your password. You log out by visiting the last tab of your Settings.
If you don't have access or if you forgot your password and are logged out of the app, try to log in with your email. The system will recognize that you already are an existing user and ask you for your password. On that screen, you will see a link "Forgot your password?" - click on it and you will receive an email with a link to reset your password. Follow the link, reset your password and go back to the Instantgo app to log in with your new password.