How can i import more fields in a invoice - eg PO Number? I would like to import all the fields recorded in an invoice?

Thank you for adding a post here on the Community page, @Stephanie1708. I'm here to share some insights about importing more fields in an invoice.

You can have up to 12 active custom fields for each type of form (invoice, estimate, purchase order, expense, bill, and so on), and each type of profile (customer and vendor) if you're using QuickBooks Online Advanced. For QBO Plus and the Essential version, you can add up to three custom fields only. 

To add the PO number to your invoices, you can either go to the settings or the Custom form styles section of your account. Let me show you how.

1. Click the Gear icon in the upper-right corner.
2. Select Account and Settings under Your Company.
3. Go to Sales.
4. Under Sales form content, add the field.
5. Hit Save and Done.

To add extra fields using a specific invoice template, please follow these steps:

1. Click the Gear icon in the upper-right corner.
2. Select Custom form styles under Your Company.
3. Choose a template.
4. Press Edit below the Action column.
5. Go to the Content tab, then click the pencil icon in the upper-right of the form.
6. Scroll down and select + Custom field.
7. Add the field and hit Done.
8. Open an invoice.
9. Press Customise at the bottom, then choose the template.
10. Enter the PO number.

For additional reference, I've attached a link you can use about how to fix errors when uploading custom form styles in QuickBooks: Import custom form styles for invoices or estimates.

You can check out this article on how to customise the appearance and layout of sales forms is a simple yet effective way to enhance your business communication: Customise invoices, quotes, and sales receipts in QuickBooks Online.

Feel free to post again or leave a comment below if you have any other questions. I want to make sure everything is taken care of for you. I'll be here to help. Have a good one!