installing applications on a user’s desktop

I’m trying to understand desktop support and I’d like to get a job doing it.
On a windows network with active directory. How do you install software on a user’s pc. I know many users usually can’t install apps. If I’m not mistaken the desktop would have a software center or a store but I want to say a normal user probably wouldn’t have the ability to do installs. But it seems to me if you log on under your user id and install the app wouldn’t that just install it under your user profile and not the actual user who needs the application?