Payment
Card and other methods are handled by the payment providers; card details never touch intelligent.page.
Invoices
Past payments are listed under Billing.
Upgrading
Takes effect immediately, and the new allowances apply straight away.
Cancelling
Stops the renewal. You keep access until the end of the period you have already paid for, and nothing is deleted when it lapses.
Buying a shared dossier
If you have paid to unlock a dossier someone shared with you, that is a one-off purchase rather than a subscription. See Selling a dossier.