Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Mary, Office Home and Student 2019 and Office 365 are two different versions of Office. Office Home and Student 2019 is a one-time payment version of Office. Microsoft Office 365 is a subscription version of Office, that is you must pay a subscription either monthly or yearly. You cannot run both versions of Office at the same time on the same computer. If you just want Office Home and Student 2019 then you should uninstall Microsoft Office 365.