From the iOS app (for iPhone or iPad) you can log in with the following methods:
If you don't recall your password, or you never set one, you can reset it from here.
If you signed up with a different method (e.g. Facebook), you can still log in using the email associated with your account. If you don't recall which one, you can chat with us and we can help you.
If you have an Agency/Multi-account, make sure you click on its dedicated option at the bottom of the login page.