Multi-account is a feature built for clients who want to integrate multiple stores in Klaviyo using one login. To use this feature, you need to create a separate Klaviyo account for each store using the same email address and password. This allows you to track each account without having to log out and log back in using a separate email address. Rather, you can toggle between accounts through the switch option on the upper right of their account.
The multi-account feature also extends to your team. Any member on the team can be added as a new user to multiple accounts with their primary address. Once added, the team member will have the ability to toggle between each account on the upper right corner, similar to how the account owner would toggle.
Learn more about Multi-Account User Privileges here.