i360 v4 does not track individual password data and will require you to reset your password if you cannot track down your initial welcome email. The process to retrieve your password begins on the log-in page: https://www.i360portal.com/
From the link above, refer to the 'Forgot Your Password' text below the username and password boxes. Select that option and enter the email that is associated with your account. Your username is your email address.
The prompt will require you to follow two-factor authentication either via text or email. When you've input that information, please choose a new password.
Please reach out to Support if you have trouble receiving the code.