Plankwork is paid for by the organisation, per seat. You start with a free trial, so you can try the product with your own team before anyone commits money. Finance and IT are often different people, so the right to manage the plan is its own switch, apart from Owner and Admin.

A free trial with full access.
A plan priced by seats, bought and changed on the Plankwork website.
A billing page that shows the plan, the seats in use and the renewal date.
Clear banners when a trial ends, a payment fails or a plan is ending.
A read-only state that keeps your data safe and visible until the plan is fixed.

The full chapter, with every step and setting, is in the app: open your account menu and select User manual.