How to update my card, see invoices, or change plans

Account menu → "Plan & billing" (also Settings → "Plan"). The Plan & billing page shows the plan you're on, what you pay and when it renews, and where it's billed. "Manage subscription" opens the Stripe Customer Portal, where you can update the payment method, download invoices and receipts, and switch between monthly and yearly or between plans; the page's "Switch to …" buttons do the plan change too. Stripe emails receipts to the address on your account.

If the page says your plan is billed through Google Play or the App Store, change or cancel it in that store's subscriptions (the button on the page says which). If you don't see "Manage subscription" and no store is named, your plan isn't billed through Stripe (for example a granted trial); tell me and I'll connect you with the team.