Then, you can start uploading invoices. Here's how:
Go to Settings ⚙ and select Import data.
Select Invoices.
(Optional) Under the Browse button, you can select the checkboxes to add new customers, products, and services that don't already exist in QuickBooks.
Click Browse and then find and select the spreadsheet of your invoices, then Next.
Map fields and VAT codes.
Once you’re done, click OK.
If some invoices fail to import, note why then select Done.
If you have prepared the CSV by following the steps but are unable to import the file, it may be due to a corrupted file error. To fix this, copy all the data into a new CSV file, save it to overwrite the potentially corrupted, and try to import it again.