Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Hi Shelly, first make sure that you have cancelled your Microsoft 365 Personal/Family before you uninstall it.
Then you can sign in at Services & Subscription of the Microsoft Account associated with your Office 2019 (the one you used to redeem your Office 2019). Here is a link: https://account.microsoft.com/services You should see as below an install link for your Office 2019. You MUST uninstall Office 2019 from your old computer before installing/activating it on the new computer. Keep both computers turned on and online during this process. It may save you from having to contact Microsoft Support to activate the new installation.