As Microsoft pushes out updates your subscription will automatically update your applications. Microsoft Office 365 continually updates.There are a few other differences though as you might expect: So if you pay for Office 2019 you own it and can use it forever without paying any more for it.

Office 2019 is a one-time purchase whereas Office 365 is an ongoing subscription service. The key difference between Office 2019 and Office 365 is how they are paid for.