You can run a guest machine in a window, so that a full Windows desktop appears in a window on your Mac or you can run a Windows desktop full-screen on a Mac, almost as if your Mac was a true Windows machine. Like other virtualization apps, VirtualBox lets you run one or more guest systems from its VirtualBox Manager menu. VMWare Fusion also costs $79.99 (for the least expensive Basic version), but that gets you a permanent license to the software. A license for Parallels Desktop, by comparison, costs $79.99 per year. Like VMware Fusion, Virtual Box is available in Mac, Windows, and Linux versions, and supports almost any Intel-based emulated system you could want, including ancient ones like DOS and OS/2. That said, this free utility makes up for these shortcomings with speedy performance, access to a vast third-party library of prebuilt VirtualBox emulated systems, and all the flexibility that advanced users could want.

Compared with the subscription-based Parallels Desktop and the buy-once use-forever VMware Fusion, Oracle's VirtualBox offers fewer automated conveniences, uses less elegant menus, and lacks as many deep integration features. VirtualBox 6.0 is the no-cost, open-source virtualization app that may be all you need for running Windows or Linux apps on your Mac, especially if you're willing to get your hands dirty.