I cannot see the description in the General Ledger when I make payment for an invoice I already posted. What am I doing wrong?

Hello there, BCc55.

If you mean that you want to view the Description column when receiving payment of the invoice, we can only see it on the Invoice age itself. Let's take a look at these sample screenshots:

Also, from the Chart of Accounts, we'll need to open the invoice to see the Description you've added to this transaction. 

1. Go to Accounting on the left panel.
2. Select the account where the invoice/payment is deposited.
3. Click the transaction you want to view the description.
4. Hit Edit.

Also, you may want to run a report that shows the Description you've added to all the transactions.  Here's how:

1. Go to Report on the left panel.
2. Enter General Ledger in the search field.
3. Click Customize at the upper-right corner.
4. In the Rows/Column, select Memo/Description.

To learn more and for additional guide when modifying and printing reports in QBO, you can check the articles below:

• Learn how to get the most out of your financial reports. 
• Common custom reports in QuickBooks Online.
• Memorize reports in QuickBooks Online.

Let me know if you have other questions. Take care always!