At one point, I needed to download MS Store application for offline installation and packaging via SCCM or OS deployment task sequence. I don’t quite remember now what it was, most probably some HP tool related to hardware certification for a customer.
Why do that? Well, via MECM, there is no good way to install these MS Store applications during OS deployment task sequence – simply because the Store requires license checks and other processes that you are able to run only when a user profile already exists on the machine. But that is not possible during OS deployment. So the safest bet there is to deploy the application after the machine is deployed.

There is cool website that let’s you extract the MS Store applications for your offline use:

You need to enter the MS Store application link there (you can get that by googling the application on the MS Store). Here is an example for Sticky Notes – it let’s you view and download multiple versions of the app and can be also split by architecture (x64 vs. x86 vs. ARM etc.).

Sticky Notes Search on the Generator

Most apps have also some pre-requisites and those are usually listed there also – like Microsoft .NET Native Runtimes or VCLibs, which you might need to install before your actual app.

The usual extensions these apps have are .Appx or .Appxbundle.
To install these, in Windows 10, you need to first enable app sideloading or developer mode:

Windows 10 Developer Features

Then, you can either simply double click the file to install it via App Installer GUI:

Application sideloading via App Installer GUI

Or install the Appx applications via Powershell:

Add-AppxPackage -Path "C:\Path\to\File.Appx"