Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Hi, which versions of Office 2019 do you see at https://account.microsoft.com/services ? The only valid ones would be Office Home and Student 2019 or Office Home and Business 2019. You will have difficulty with any Pro Plus licence for various reasons depending on where you acquired it/them. In any case you will need to contact Microsoft Support to 'deactivate/delink' the Office 2019 installed on the old computer.