To remove two-factor authentication, go to the My account menu and click ‘Two-factor authentication’. Then click the ‘Remove two-factor authentication’ button at the bottom of the page. This will turn it off on your account.
You also need to make sure you unregister your device. You can do this by opening the app, generating a login code, and clicking the ‘Unregister device’ button.
You can re-enable two-factor authentication at any time.