Screen recording on Mac with the sound included

Heads up for the BlackHole route: once you're on a Multi-Output Device, the volume keys stop working and the menu bar volume is greyed out. You set the level in the app instead, or switch back to your normal speakers when you're done recording. And if what you're recording is a Zoom or Teams call, their own record button captures everyone's audio with no setup at all.

This trips everyone up. Cmd+Shift+5 (and QuickTime) only record the microphone, not the sound the Mac itself is playing, so you get your room and nothing from the video or call. Two ways round it that I know of: OBS. On recent macOS versions it can capture app and system audio directly, no extra drivers needed. Or install a virtual audio device like BlackHole, then in Audio MIDI Setup create a Multi-Output Device with BlackHole plus your speakers or headphones. Set that as your output and pick BlackHole as the mic in the screenshot toolbar options. Bit fiddly to set up, but once it's done it works every time.