Welcome to the Community, @macque-bohleen.
To ensure I'm on the same page, I can provide you with the following scenarios below and what you'll need to do to achieve your goal.
When you upgrade QuickBooks Desktop to a new version, you can restore the old company file or create a new one. If you want to open the old company file on the new version, it'd be best to create an extra backup so you can still open it on the older version.
Also, be sure to check the system requirements first before you proceed. They may differ depending on the version. You can check this link for QuickBooks 2020 requirements: System requirements for QuickBooks 2020 and Enterprise Solutions 20.0.
Once you're ready, you can perform the steps outlined here: Upgrade to newer versions of QuickBooks Desktop Pro Plus, Premier Plus, or Enterprise.
However, if you need to migrate from QuickBooks Desktop to QuickBooks Online, be sure you haven't set up anything on the Online version for a smooth process. You can check this guide before deciding to switch: What to expect when you switch from QuickBooks Desktop to QuickBooks Online.
Whenever you're ready, you can perform the steps on this article for the conversion process: Move your QuickBooks Desktop file to QuickBooks Online.
For additional questions or clarifications, please comment below. I'm here to help however I can. Take care and have a nice weekend.
