Is there a Invoice/Payment transactions summary template that can be used to import data into QBO from a POS system?

Yes, you can import a CSV file for an invoice and upload the payments as bank transactions to QBO, @slarmond.

For the invoices, you can download a sample file to reference the format using a spreadsheet before importing.

Here's how:

1. Go to Settings ⚙.
2. Select Import data.
3. Choose Invoices and click Download an example.

To upload the spreadsheet, follow the steps below:

1. Go to Settings ⚙, and click Import data.
2. Select Invoices, click Browse, then select the spreadsheet for your invoices.
3. Click Next.
4. Map the column headers with QuickBooks Online invoice fields.
   • Fields with an asterisk (*) are required.
   • Select Not applicable for any fields not in your spreadsheet.
   • Note: QuickBooks automatically fills in a default item labeled sales for any missing products and services.
5. Choose the date format you used, like D/M/YYYY.
6. Click Exclusive or Inclusive as your sales tax option. To see this option, set up tax codes in QuickBooks and hit Next.
7. Match your tax codes to those set up in QuickBooks, then click Next.
8. Select Start import.
9. Click OK.
10. Hit Done.

I'm adding this article as your reference to learn more about importing invoices in QuickBooks Online: Import multiple invoices at once in QuickBooks Online.

Also, upload the payment transactions by following the steps in this article: Manually upload transactions into QuickBooks Online.

For future reference, click this link for the common questions about importing data: Common questions about importing data to QuickBooks Online.

You can always comment below if you have questions about importing data to QuickBooks Online. I'm always here to help. Have a great day.