A subscription offering is the actual pricing configuration for a specific product variant (SKU). While a subscription plan defines the rules and structure (billing periods, metered variables, etc.), the offering applies those rules to a product and sets the concrete prices customers will pay.
This is where you connect your subscription model to your product catalog.

You can configure subscription pricing in different ways depending on your business model:
In the screenshot above:
This makes it easy to model SaaS-style subscriptions with per-user billing that scales as customers grow.