Blossom invoices you for the platform itself. These are the platform's invoices, not yours — they live in the Subscription tab's Billing section, not in your Sales module, and nothing about them touches your own books until you record them there.
Each invoice shows:
- its number and its state — open, paid, or failed (a failed invoice is still payable, §15.5);
- the plan and the price it was struck at — your protected price under §15.3's lock, which may be below today's list price, and says so;
- the billing period it covers, and the amount;
- the due date — the issue date plus the grace period.
A paid invoice, with its payment recorded against it, is your receipt, and the Billing section keeps the set — open and paid — so your own accounts can be squared against them: from your side of the counter, a subscription invoice is simply a supplier's bill (Chapter 4's paperwork, pointed the other way), and the section is where its paper lives. Plan changes are never prorated, so each invoice prices the plan you held for its period under the price-lock rules — one invoice, one period, one plan.