Error message received is square app transaction needing general ledger code. Where to you add the general ledger code for app transactions in order to add?

I'd like you to seamlessly enter the general ledger code in your Square transactions, @arborist-downtor. This way, you can categorize them without a moment's delay.

Let's get your square app running by disconnecting in QuickBooks Online. This way, the connection will refresh.

Do the following: 

1. Log in to your QBO account. 
2. Select Apps in the left menu and click My Apps.
3. Locate Square Reader, then hit Disconnect. 
4. Follow the on-screen instructions. 

After that, I suggest you re-connect the app and check if you can add the general ledger code seamlessly. 

If the issue persists, I'd recommend contacting square support. This way, they can review your app settings on what caused the problem. They can also provide other troubleshooting steps to help fix the issue. You can visit this link to reach them: Square Support Team. 

Once fixed, go to the Banking page, choose the App Transactions tab, and categorize them. This way, your books will stay accurate at all times. For complete procedure, check out this article: Categorize and match online bank transactions in QuickBooks.

To ensure your financial data is accurate, I'd recommend reconciling your Square account. It will effectively monitor your income and detect any possible errors accordingly. Refer to this article for the complete step: Reconcile an invoice in QuickBooks Online.

Just hit back in this thread. I'll be here if you need further help with your banking transactions. Take care always.