How can I prepare an estimate or invoice and have sub groups for the services in them such that items in each group appear on the estimate in different sections.

Hi there, @ayo-ogunlade.

We can group your product and services to keep things organized with your estimate or invoices in QuickBooks Online. Let me guide you how to do it.

1. Go to Sales in the left menu and select Product and Services.
2. Find the product or service you want to group.
3. Click the ▼ drop-down,from the Action column.
4. Select Run report
5. Click Customize then select Rows/ Colums.
6. Below the Group by click the ▼ drop-down then choose Product and Services.
7. Hit Run report.

Once you've done, the items in each group will show on the different sections and you can get a snapshot of various aspect of your business..

To learn more about the process, please refer to this article: Group your products and services into different categories.

Also, I'll add this article on how to personalize your form designs in QuickBooks Online: Customize your invoices, estimates, and sales receipts.

Feel free to leave a comment below if you have any other concerns. I'll be here to help. All the best.