Windows runs great on a Mac, but if you only need to run a few specific Windows application on your Mac, then you might be able to do just that without needing to go to the expense or hassle of installing Windows on it.
Here I'm going to look at two applications - one free, one a commercial product - that will allow you to do just that.
The first is Wine. This is a program - actually, it's a compatibility layer, but that's rather a mouthful - that has its roots in Linux, but also works on OS X. Wine is far from perfect, and can't handle every Windows app, but it still offers pretty broad support for a whole range of Windows applications.
Wine itself doesn't offer an OS X download, but the third-party application WineBottler brings everything Wine has to offer to the Mac. And best of all, it's free.
WineBottler is fully compatible with OS X 10.11 El Capitan.
Prefer a commercial application? No problems. Take a look at CrossOver for Mac. Not only is CrossOver compatible with thousands of Windows applications, but you can also try installing unknown and untested Windows application into it. Many times they just work, and those that don't work perfectly might work well enough for your purposes.
Subscriptions start at $40, and there's a free trial available so you can test it before committing.
Neither of these products beats actually running Windows on your Mac, but if you only need to run a small number of applications then taking this route can save you money, hassle, as well as precious disk space on your Mac.