Propfy bills in US dollars through Stripe. That is the only payment rail; there is no second gateway and no other currency.
Monthly or annual. Monthly renews every month and can be stopped at any time. Annual is charged once for twelve months at the equivalent of ten. If you are not sure which suits you, start monthly.
Subscribing. Pick a plan on the pricing page and pay by card through Stripe. Your plan unlocks once the payment clears.
Changing or cancelling. Both are self-service, from your account settings. You can cancel a subscription, resume one you have already cancelled, and open the Stripe billing portal to update your card or download an invoice. A cancellation takes effect at the end of the period you have already paid for, so you keep access until then.
What happens if you stop paying. Your data stays. Your journal, trades and history are not deleted when a plan lapses, and the paid features come back the moment the plan does. If you want your data removed instead, that is a separate and deliberate action you take from your account settings.
Refunds and disputes are handled by a person, not a form. Open a ticket.