The program is provided by Microsoft for large customers, only 4MB, see attachments, download and install. You can only download and install the VL serializer for activation. Unlike the way Office 2016 for Mac is activated, 2019 no longer supports the activation of simple copy-and-paste authorization files. Instructions for activation: 16.17 is listed in the Office 2019 series by Microsoft and will use the VL of the 2019 product (large customer license).
Office 2019 for Mac only supports macOS 10.12 or newer! If the user is using OS X EI Capitan or earlier, they will only be able to install Office 2016 for Mac, and the version number will stay at 16.16.X. The 16.17 version previously released on September 12 is 2019! See the screenshot below for an update description. On September 25, Microsoft officially released Office 2019 for Mac.