Emulation on iOS for Apple iPhone, iPad, and the Vision Pro headset continues to mature, with the first free PC emulator, 'UTM SE,' now available on the App Store. Interestingly, Apple rejected the app in June, even though it had changed its policy on consoles and other retro gaming emulators. According to Apple, a PC is not a console; however, with a few changes, the app has been approved for distribution.

UTM SE is a PC emulator for macOS and iOS designed to run various recent and retro PC operating systems, from Windows XP to Windows 11 to Linux and retro versions of macOS. It emulates "x86, PPC, and RISC-V architectures" with graphics-based and text-only operating system support.
That said, the emulator's PC gaming chops have one fundamental limitation. "UTM does not currently support GPU emulation/virtualization on Windows," which means no 3D acceleration via OpenGL or DirectX - so you're limited to software rendering. Still, this covers a long list of classics.
Windows games with software rendering include Need For Speed, Hexen: Beyond Heretic, Destruction Derby II, Quake, Star Wars: X-Wing vs. TIE Fighter, X-COM: Apocalypse, Tomb Raider II, and many more. Granted, many classic PC games that offer software and hardware accelerated rendering generally look and perform better with the latter - but it's still nice to know that if you're pining for a late 1990s PC experience, you can have exactly that on an iPad without having to bust out an old CRT monitor and a beige tower. Plus, you've got all the big MS-DOS games to fire up.
UTM is bare-bones out of the box; you'll need to check out the developer's site for guides and tutorials on installing older Windows or even MS-DOS versions.