In the win10 UWP with non-store, install app should open developer-mode or side-loading mode.
However, My company have high security level. I can\'t change any setting f
Install UWP without developer-mode and sideloading
If you want install app within non-store, non-sideload, no-developer mode, the better way is that use line-of-business apps. However even using this way you cannot completely isolate Microsoft store
Your company or school can make line-of-business (LOB) applications available through Microsoft Store for Business or Microsoft Store for Education. These apps are custom to your school or organization – they might be internal apps, or apps specific to your school, business, or industry. For detail steps please refer this document.
Distribute apps to your employees from Microsoft Store for Business and Microsoft Store for Education. You can assign apps to employees, or let employees install them from your private store. Please refer this document.