Hi there, @Nomuddyaffair.

Let me help you map the fields correctly. Since you're able to use the sample file as your basis, make sure that you have removed the additional text written when editing the CSV file.

Also, ensure that all the date format is the same as the saved CSV file. Please see my attached screenshot below:

Here are the things that you're able and unable to import in QuickBooks Online:

• You can’t add discounts, credit notes, and negative amounts in general.
• You can import a maximum of 100 invoices at a time and 1,000 row limit per spreadsheet.
• You can import invoices with single or multiple line items.
• You can also import a large volume of customers and suppliers or products and services.

For the detailed steps and information with mapping and importing invoices in bulk, you can review this article: Import multiple invoices at once.

Additionally, since you've mentioned that the date in columns is displayed as special characters, I suggest going through these steps:

1. Open your browser's private window. This isolates the cache, which is the usual cause of unexpected behaviors in browsers. 

• • Google Chrome: Ctrl + Shift + N
  • Microsoft Edge: Ctrl + Shift + P
  • Firefox: Ctrl + Shift + P
  • Safari: Command + Shift + N

1. If that works, go back to your regular browser clear its cache. 
2. If the issue persists, open an alternative browser available for you. 

Please let me know if you have additional questions. I'm here to help you anytime. Have a safe day ahead.