How to upload invoice from CSV file where "Invoice Date" only support single Digit? e.g 3/24/2021 , 12/12/2021 . .the list for upload is NOT support format above

Welcome to the Community, globaldealmy.

I'm here to help you ensure that you can import your CSV file in QuickBooks Online.

Before you can import your invoice, you'll have to make sure that each line item entry has an invoice number, customer, invoice date, due date, item amount, and item tax code if applicable. Please take a look at what's required to import the invoice or download this sample spreadsheet.

The CSV file and QuickBooks date format should be the same. If no, you can open the file and manually change it. I'll show you how.

1. Locate and open your CSV file.
2. Click the Date column, then right-click and select Format Cells. 
3. Make sure that CSV file and QuickBooks available format are the same.
4. Once done, hit OK then save your CSV file.

That should be it. You can now import your CSV file. For your reference, you can check this guide: Import multiple invoices at once. This contains detailed steps to import your file in QBO.

I'll get back to you if you have further questions about importing files. Just reply to this post. Stay safe!