That may be by emailing them a video file, or uploading the result to a video sharing site. That could be displaying your desktop, an app, several apps, a game or a combination of them all as you work through a problem or tutorial that you want to show someone else.
We’re not talking about video editing software here, though some will have basic editing tools built-in, but software that captures the output of your computer’s screen. Trying to capture your screen with software that’s not up to the task can lead to sub-standard video, and if you’re showing your captures to someone important, then only the best will do. It’s a simple equation, as with video you get out what you put in. If you want the best video captures, then you need the best video capture software.