Hi remingtonsven,
Welcome to the community! QuickBooks Online has powerful tools in place to enable you to track your transactions. Being able to see where these transactions go in the GL is a great way to ensure accuracy in your books. I'll be happy to assist you with this.
The accounts used by the program to track your transactions depends on your settings. After recording an invoice in the system, you can access the Transaction journal of that invoice to view where each charge and taxes went. To do that, simply open the invoice and select More at the very bottom, then Transaction journal. The Accounts column will present accounts linked to every charge on the invoice as well as that associated with your shipping charge. Another way to know in which account your shipping charge goes is to view its settings in the Product and services menu and identify the Income account you selected for it. Here's how to proceed with that. Go to Sales > Product and Services > Locate your shipping charge service > Edit > View the Income account.
Once you know where in the GL your charge goes, you can now access it in your chart of accounts by going to Accounting > Chart of account, and selecting Account history or Run report for the desired account.
I hope this helps! Feel free to stop by if you have any other questions.