Only workspace admins can update the workspace's payment information.
Mixmax billing is handled through Stripe. To update your credit card:
Go to Billing in the Admin center.
Under Current Subscription, click Manage on Stripe.
You'll land in the Stripe customer portal. Update your card there.
In the Stripe portal, you can add new cards, remove old or unused cards outright, set a default payment method, and update card details (like the billing address or expiration date). Your invoices and receipts are also available there to view and download.