I use installing of my UWP application via .appinstaller file: Read more about this approach
But now the installation works only for current user. Could I somehow insta
You cannot do this from a package manually installed (double clicked) by an user.
System wide deployments are available only if you use Microsoft's DISM tooling. More details:
https://superuser.com/questions/647927/install-windows-store-app-package-appx-for-all-users
https://social.technet.microsoft.com/Forums/ie/en-US/164caad9-68f7-43c5-9a66-716b3b5a0a73/how-to-install-appx-packgage-for-all-users-using-addappxpackage-command-using-powershell-?forum=win10itprosetup