How can i transfer a copy of my company file from online to desktop while keep the online file active too?

You can purchase a 3rd party conversion service.

Hi there. Just to add to the valuable info offered by 4Gal above, you can automatically transfer your data from one program to another using a third-party migration app. You can search for these apps on our app store www.apps.com. You also have the option of manually transferring your data from QBO to QBDT while keeping the Online version active.  Since QBO is separate from QBDT, you'll have to manually export your data out of QBO to QBDT. Here's how to export your reports:

1. Select the Settings ⚙ and then Export Data.
2. On the Reports tab, set the date range.
3. Add or remove items from the Reports and Lists tabs by toggling the slider.
4. Select Export to Excel.

I encourage you to check out the articles below as they also provide more export options out of QBO:

Export reports, lists, and other data from QuickBooks Online

Export your reports to Excel from QuickBooks Online

Once you have the desired information in Excel, you can then import the data into QuickBooks Desktop. There are several options for going about this, so I recommend reviewing those steps within this article: Import or export MS Excel files. Here are some other helpful resources that show you how to: 

• Download QuickBooks Desktop
• Install QuickBooks Desktop

If you're completely moving your accounting from QuickBooks Online to QuickBooks Desktop, I recommend reviewing this article as well: Move lists and balances from QuickBooks Online to QuickBooks Desktop. This resource gives a comprehensive explanation of the process, and what order to complete the steps in. Let me know if you have other questions, I'm here to help steer you in the right direction.