Loop’s a tool for real-time collaboration where you organise your projects in Workspaces which consist of Pages and Components.
If you want to create a new Loop Workspace or add/remove members in a Workspace you need a Microsoft 365 Business Standard/Premium or E3/E5/A3/A5 licence.
This requirement was waived during the public preview period for the Loop app, but came to an end on December 31, 2024, so now all users have access to features based on the Office 365/Microsoft 365 plan that they have.
Find details on this and general Loop licensing information here: https://bit.ly/4hio0cK.