I’ll guide you on posting your products and services to your desired accounts in Profit and Loss.
Initially, you can create a new account in the Chart of Accounts. Once done, edit or create a new item in your Product and services and customize the income and expense account. This way, when you use this item, it will be posted to different accounts.
Go to Sales and choose Products and Services.
Edit or create a new item.
Enter the needed information.
Choose an item under the Income account.
Select an item under Expense account.
Click to Save and close.
You can check this article to learn more about managing your account in QuickBooks Online: Help articles.
Should you have any other concerns, I’m always here to help.