The Store app is an Universal App … but it has a quite strange interface behavior!
You surely know that Universal Apps can change completely the user interface according mainly to the dimension of the screen but even possibly to the type of device (e.g. mobile, desktop) … and this is what happens in the Store app and may be, in this case, it can make you be confused and you can wonder how to force an app update check when it is running on a Windows 10 desktop device!!!
If you are used to Windows 10 Mobile, you know that there is a hamburger menu on the top left that shows a list with the specific item “Downloads and updates” for forcing that check: on the contrary, if you see that app on a PC (at least if it is in full screen mode or in a big windows!) you can’t see the hamburger icon on the upper left … and you may wonder how to do that!
Then, if you click on your user icon (on the top right) you can have the wanted menù appear … and possibly you may doubt that this app is really an Universal App being this behavior so different from the one you have on Windows 10 Mobile!
But if you dimension the window smaller enough, you can have your user icon disappear and the hamburger menu be shown … like it is in Windows 10 Mobile!!!
The same happens for Settings and others voice menu: