How do I post a negative opening balance on my credit card account?

I'm here to lend a hand, highgrove.

I can show you the steps on how to post a negative opening balance on your credit card account:

Here's how to complete the process:

1. Click the Gear icon at the top. 
2. Select Chart of Accounts. 
3. Pick the New button at the upper right hand in the Chart of Accounts page. 
4. Enter the Account Type, Detail Type, Name, and other necessary information. 
5. In the Balance section field, enter the negative opening balance amount as well as the date. 
6. Click Save and Close. 

However, if you didn't enter an opening balance on your Chart of Accounts, you can see below article for guidance on how to handle it:

What to do if you didn't enter an opening balance in QuickBooks Online.

 If you have any follow up questions, please let me know. I'm here for you. Have a great day.