The Billing tab (/o/{organization-slug}/billing) shows payment customer data, subscriptions, and (when enabled) a plan picker. You need the billing permission to open this tab; otherwise it stays disabled with a tooltip.
When a billing customer exists for the organization, you see:
If the organization has a core product / subscription, a card shows:
Actions (when applicable):
Depending on feature flags and whether you already have a subscription, you may see:
Exact copy and which blocks appear depend on your environment (demo vs production, pricing enabled or not).