Business Credit Card splits into 3 different cards but payment only goes to the "main card", how to join all cards together?

Welcome to the Community space, @Dan1948. We'll provide details to help you get through this and have all your bank accounts and transactions under one business card account in QuickBooks Online (QBO).

As we read your post, it looks like you're referring to having sub-accounts linked to the Parent account, which compiles all transactions you have in those sub-accounts to your Main account or Parent account.

Please know that in QBO, you can't connect the parent account and its sub-accounts. That said, you'll want to connect those credit cards to your main credit card, which shows you the total balance of the overarching business card account linked to your company. We'll write down the steps below to get you going:

1. Access your QuickBooks  Online company.
2. On the top-right corner, click the Gear icon and then select Chart of accounts.
3. Find the account you want to edit.
4. In the Action column, select the View register menu▼. Click Edit. Depending on your account view, you’ll either see the Account or the Edit account panel.

For further guidelines, please see the Change an existing account into a subaccount section inside this article: Create subaccounts in your chart of accounts in QuickBooks Online.

In addition, here's an article to help you manage bank transactions and reconcile an account inside the program:

• Categorize online bank transactions in QuickBooks Online.
• Reconcile an account in QuickBooks Online.

We look forward to having you here again if you need further assistance managing bank accounts inside the program, @Dan1948. Feel free to comment below anytime so we can help you out again. Keep safe.

Im actually trying to make 1 of the 4 accounts the "parent" account but keep getting this error:

"You can't change the parent of this account to Visa BOA XXXX- primary card because it or its parent is already set up for Online Banking or Web Connect. " 

So therefore QBO won't let me set up the parent account when the account already exists 

We appreciate you replying about your follow-up concern in the thread, @Dan1948. Let me help you further regarding setting up a parent account inside QuickBooks Online (QBO). 

To answer your question, Yes. You can't set up a parent account to an account connected to online banking. I suggest disconnecting the account to set up the parent's account successfully. Here's how:

1. In Transactions, go to Bank Transactions.
2. Click the tile for the bank account.
3. Hit the pencil icon, then choose Edit account info.
4. On the save checkbox, select Disconnect this account.
5. If done, hit Save and Close.

After that, you can now make a parent account. Scan this article as your reference: Add an account to your chart of accounts in QuickBooks Online.

Moreover, I recommend reviewing this post as your additional knowledge of how credit card accounts are treated for cash-basis statements inside QBO. 

Don't hesitate to reply below for further queries regarding managing your accounts. We're here to assist. Have a good day!