Microsoft has just announced Office 2019 is now available in preview.
You need to register at https://go.microsoft.com/fwlink/?linkid=872092
It is important to note that Office 2019 will only available in Click to Run installation mode; no more MSI installation package available.
You will be able to upgrade from an MSI package installation to Office 2019.
To have a complete list of the features available, go https://go.microsoft.com/fwlink/?linkid=872297