To start, exactly as it was displayed on my own Mac OS X El Capitan system, here are some folder and file icons: That’s pretty easy to do, but let’s look at all the different options and how they can affect what’s shown on-screen. So instead of artificially lowering the resolution of your Mom’s Mac screen, the better solution is to tweak the Finder settings for the Desktop.
You can experiment with that by going to the Display System Preference, but there’s a much smarter way to fix things! After all, change the resolution and every program suffers, even the games, streaming video content, and Web browser, so I always see that as an option of last resort.
The classic way to make everything on a computer screen larger is to lower the resolution: the smaller the computer thinks the screen is, the larger everything ends up being to compensate.