In order to use LiveFlow or be added as a user to another user account LiveFlow account, you will need an email address tied to Gmail.
If you or someone on your team doesn't have an existing Gmail account, you can utilize one of two methods to access/be added to LiveFlow.
Method 1: Open a Google Workspace Account
You and any users you add will need to have an account with Google Workspace.
Google Workspace is the suite of applications, including productivity and collaboration tools, software and products developed by Google (think: Gmail, Drive, Calendar, Meet, Chat, Doc, Sheets, Slides)
To open a Google Workspace account, please learn more here.
Method 2: Create a personal Gmail account just for LiveFlow use