When another user adds you to Snapfix with an email address, you’ll receive an email with instructions on how to download Snapfix and which email address and temporary password to use. Make sure to check your Spam folder
Navigate to the login page and use your email and temporary password to login. You'll be asked to update your password. NOTE: don't try to register another account with the email address, as you'll receive an error message stating that an account already exist.
If you can't find the email, you can use the password reset with your email which will trigger a new password to be send to your email address.