Does anyone know if the Quickbooks Desktop Pro 2019 is compatible with downloading a company file from Quickbooks online?

You can migrate it and visit this link for your reference

https://quickbooks.intuit.com/learn-support/en-us/install/how-do-i-convert-from-quickbooks-online-ba...

Hello there, @kristinlmt12.

QuickBooks Desktop Pro 2019 and other QuickBooks Desktop versions are compatible with downloading a company file from QuickBooks Online.

Please take note the following when you convert from QuickBooks Online to QuickBooks Desktop: 

• You need Internet Explorer 11 installed to complete these steps.
• You must be logged in as the administrator in both the Desktop and Online accounts.

For more details about the limitations when converting the data, as well as the steps on how to export the file, you can use the following articles:  

• What does and doesn't export 
• Move your data from QuickBooks Online to QuickBooks Desktop

If you have questions about the conversion or anything else, please let me know. Have a great weekend.