Ted here from Shopify, thanks for posting your query!
Can I just ask a little more about what you mean by this? The reason I ask is because it is not possible to add a credit card to Shopify Payments.
Are you looking to remove your credit card from the Settings > Billing section of your account? If so, it wouldn't be possible to remove the card unless you close the account as mentioned here. Have you selected a plan as of yet? If not, you won't be charged for a subscription unless you pick a plan.
If you tell me a little bit more about the set up you have, I'm happy to chat further! Our 24/7 support is also available here if you would prefer a faster response. Just click Support > Contact Support in the main menu for assistance.