I clicked 'pause' and shut down my computer, expecting the download to resume when I re-opened the Microsoft Store UI (the same way that, say, Steam will resume an interrupted download). The download was very large and I was unable to finish it that night. That was fine, I had 32 GB free on my C: drive, so I clicked OK and started downloading. At the beginning of this process, I was informed that I'd need some relatively large amount of free space (about 24 GB). I began downloading and installing it via the UI.
Yesterday, I purchased a game (The Outer Worlds) via the Microsoft Store.