I would like to add extra lines after the business details in the top section of a 'modern' template layout. How do I change the size of sections in QB Online?

Good to see you here, wrwightman-hempf.

I'll be glad to help. For now, you can only adjust a few things in the template, such as the page margins or labels and widths on the activity section.

Here's how:

1. Go to the Gear > Custom form styles.
2. Select the Edit link of the template you want to modify.
3. In the Design tab, click the Edit print settings option.
4. Adjust the margins to your preference.
5. Go to the Content tab and press the EDIT LABELS AND WIDTHS link. Make the necessary adjustments.
6. Hit Done.

For reference, check out this link: Customise invoices, quotes, and sales receipts in QuickBooks Online.

The other way on how you can achieve this is to import a template from a Word document. Before doing so, let's make sure to enable the import option in the settings.

Here are the steps:

1. Click the Gear > QuickBooks labs.
2. Turn on the Import Style option.

Please see this sample screenshot for a visual reference:

Go back to the Gear > Custom forms styles > New style > Import style. You can check this article for more information: Import custom form styles for invoices or estimates.

If you need more help with your QuickBooks Online account, please feel free to leave a reply below. I'll be around to help you out again. Take care and stay safe!