Without the Microsoft Store app, you won’t be able to install apps from the Store. If Store is missing, you can promptly skip to a second step. If, however, it is installed but it's not working, remove it first.

COMMAND: Get-AppxPackage *windowsstore* | Remove-AppxPackage

In order to restore or reinstall Microsoft Store, start PowerShell as Administrator. Click Start, type PowerShell. In the search results, right-click “PowerShell” and click Run as administrator. In the PowerShell window, type the command given below and press ENTER. This should install/reinstall Windows Store app. After the process ends, reboot your PC to complete this action.

COMMAND: Get-AppXPackage *WindowsStore* -AllUsers | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}