https://www.bleepingcomputer.com/news/microsoft/microsoft-store-brings-remote-app-install-to-windows-10-with-install-on-my-devices/

Microsoft has added a new feature to the web version of the Microsoft Store called called "Install on my devices" that allows you to install an app on Windows 10 devices where you have an account. Similar to Google Play, this allows you to install apps on devices from the web, even if your not accessing the Microsoft Store from Windows 10.

When you open the store page for an app on the Microsoft Store, and have previously used your account to install this app, you will be shown a button labeled "Install on my devices".   In the example below, as I had previously installed Netflix using this account, the button had become available.