If you're being billed by credit card for your Matcha subscription, you'll be prompted for credit card information before you get into the app:
Once you've set up credit card billing with Matcha, you'll automatically be billed for your Matcha subscription when it comes due. You can see your next bill, and see and download up to six recent invoices, in the Billing section of Matcha settings:
You can view and update your credit card on file on the same page:
If you are not currently being billed by credit card, and would like to be, reach out to your project manager to get set up.