Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Hello Paul,
Did you purchase the subscription from Microsoft?
If so, you can go to https://account.live.com > Subscriptions, find your plan, and see the expiration date.
As for how many devices have it installed. use this link https://account.microsoft.com/services/microsoft365/install
The devices should be listed at the bottom of the page.