Yes, you can add or attach multiple credit card accounts in QuickBooks Self-Employed, marilyn.
Here's what you need to do to add the second credit card account:
Go to the Gear or Profile ⚙ icon and select Bank accounts.
In the search box, enter the name or URL of your bank or credit card. Then select Continue. If you've already connected an account before, click Connect another.
Enter the sign-in info you use for your credit card or bank's website.