Hello there, @marijke2102. I'm here to share details about importing data to QuickBooks Online (QBO). This way, you're able to keep your account updated and manage your transactions accordingly.
Based on your description of the issue above, it seems like you want to migrate data from QuickBooks Desktop (QBDT) 2003 to QBO as also verified by Fiat Lux - ASIA. Since you already have an Excel file, you can manually import it to QBO. For the complete steps on how to import your list (i.e., suppliers, customers, inventory, and chart of accounts), I'd recommend checking out this article's Import your lists to QuickBooks Online section: Move your lists to QuickBooks Online.
After importing, you can pull up the necessary reports (i.e., Profit and Loss, Balance Sheet, Customer/Supplier Contact List) to verify that the process was successfully executed. Just go to the Reports menu's Standard tab.
On the other hand, the QBDT product is available in the US, Canada, and the UK. The software has a 3-year life cycle. You'll have to go from 2003 to 2006 to 2009 and so on until the latest version. Then, upgrade your company file in between. However, you can also contact our Customer Care team to upgrade the data you have. Make sure to contact the appropriate region of which you've purchased the QBDT program. You can check out this article on how to contact our US region: Contact QuickBooks Desktop support.
In the meantime, I'm adding this article to further guide you in managing your QBO account and transactions: QuickBooks Help Articles. It includes topics about QuickBooks set up, banking, and taxes, to name a few.
Let me know how it goes in the comments below. If you have other concerns about importing your company data to QBO, I'm just around to help. Take care always.
