If your Internal team’s platform configuration allows for clients to input a credit card when signing up, then they can add a card or choose to skip and add it later.
Bear in mind that clients need a payment method on file for an order to go live automatically. If not, you would have to manually authorize each client. With that being said, once a card is added to the platform, both the client and your Internal team have the ability to update that card once you have “enabled replacing” on that client’s account.
If you would like to remove a card completely from the client’s account, there is the option to do it through Stripe. Here’s an article that should give instructions on how to do this or you could contact Stripe directly for more information.
Enable Replacing