Go to Settings → Billing.
Upgrade — choose Spark, Starter, or Growth (monthly or annual). You will complete Stripe Checkout.
Manage plan — change tier when you already subscribe.
Customer portal — update card, download invoices, or cancel. Cancellation follows Stripe’s portal rules (usually at period end).
If the dashboard still shows an old plan after you paid, use sync from Stripe on the billing card (or wait a minute and refresh).
Downgrading below your current campaign or widget count can block creating new ones until you are under the new cap. Export anything you need first.