Currently, QuickBooks Online doesn’t have a direct option to download the entire company file in one go, Mochisonsuk.

However, we can export various types of data, such as your lists, reports, and transactions.

Here's how:

1. Go to the Gear icon, and select Export data.
2. Choose either the Reports or Lists tab.
3. Use the toggle switches to add or remove items you wish to export from each tab.
4. Click Export to Excel to complete the process.
   

For further details, refer to the article: Export Your Data from QuickBooks.

If you have any further questions or require additional assistance, please add a comment below. We are here to help.

@mochisonsuk 

You can purchase a 3rd party service to convert your data to a new program.