Can i change the cards and the username and password for capital one credit cards?

You can modify your Capital One credit card username, password, and the link connected to your QuickBooks Online (QBO) account, Sharihaling. I can demonstrate the steps for you.

Before that, ensure that any changes are applied on your bank end to guarantee that any of these will be applied and will not create distortion upon connecting. Furthermore, to proceed with configuring your credit card information, kindly follow the steps below:

1. Log into your QBO account.
2. Go to Transactions, then select Bank Transactions. 
3. Pick your Capital One credit card on one of the banking tabs.
4. Click on the pencil icon, then choose Edit sign info.
 

You'll be then asked for your updated bank credentials. From there on, kindly follow the on-screen steps.
 

Additionally, this material will help manage your credit card transactions: Categorize online bank transactions in QuickBooks Online.
 

Let me know in the comments below if there is anything else I can help you with your credit card details, Sharihaling. I'm here to assist you 24/7. Have a great day ahead.