How do I copy my file from quickbooks online to desktop?

You may have 2 ways:

1. Utilize a migration tool. i.e TPExporter for Online and TPImporter for Desktop

https://transactionpro.grsm.io/qbo

2. Purchase a 3rd party migration service.

Contact us in private for details.

Utilize the trial license for QB Desktop to open your file and you can purchase the one time (outright) license of Pro/Premier later.