Choose Screen Recording from the menu File > New or a toolbar New Generator button to generate a video of your computer screen and record audio from your microphone (technically, the default audio input, which is usually the microphone). How it behaves depends on which operating system you use. This feature was added in Shotcut version 25.10, and it is not currently available in the Linux Flatpak (we hope to include it in the next version).
First of all, if you did not create a project folder it opens a file save dialog for you to choose the image file name and location. After the video is created, it opens in Shotcut’s Source player. From there, you can add it to Playlist or Timeline.
Windows
On Windows, this simply launches the Snipping Tool that comes with Windows, which shows a toolbar at the top of the screen with a drop-down button where you can choose Rectangle (default) or Window. When done with the mouse or touch to draw the rectangle or pick the window, the toolbar changes and shows a Start button. Click it. When you are done click the Stop button in its toolbar. When done, a file may yet be created, and Shotcut will not open it. Rather, the full Snipping Tool opens. It has a save button that looks like 
. There is also a menu button … with 
Settings where you can configure it to always save, and to which folder. Finally, you need to open the saved file yourself in Shotcut. A good way to do that is to use the integrated Files panel and its Videos preset location.
macOS
On macOS, there is no toolbar. Rather, it goes directly into fullscreen recording after choosing a save file. Make sure you choose a unique file name; the job will fail if you do not. It creates a job in the Jobs panel. You can minimize Shotcut yourself if you do not want to record it. (Trim the recorded video in Shotcut to remove the minimizing and restoring.) Right-click the job in Shotcut and choose Stop This Job and the recorded video should open in the Source player. If you minimized Shotcut do not forget to restore its window in order to stop the recording job.
P.S. This uses the screencapture command line utility that comes with macOS.
Linux/X11
Next, you see the following toolbar either at the top or centered on the screen:
If you do not want to include Shotcut’s window, minimize Shotcut either before or after choosing something from the toolbar. Shotcut will restore itself.
If you choose Rectangle, you need to use mouse or touch to draw a rectangle over the part of the screen to capture.
If you choose Window you need to click an application window.
A new job appears in Shotcut’s Jobs panel. It shows an updating duration of the recording. When you are done, right-click this job and choose Stop This Job and Shotcut opens the recorded video in the Source player. If you minimized Shotcut do not forget to restore its window in order to stop the recording job.
It is normal and expected if a dialog opens suggesting that you can convert this video because it is variable frame rate. You can if you want to, or click Cancel to dismiss it. You can always convert it later from Properties if you experience issues with timing.
Linux/Wayland
On Wayland, there is no toolbar, and the behavior depends on whether you are running GNOME, KDE, or something else. On GNOME or KDE, it creates a job in Shotcut’s Jobs panel and launches ScreenCapture in GNOME Shell or Spectacle in KDE.
In GNOME, when done recording, right-click Shotcut’s job and choose Stop This Job. The recorded file should open in the Source player.
In KDE, a job is created in Shotcut, but that is not where you stop it. Rather, in order to start it, you need to click the start button in the Spectacle panel that pops up. Likewise, to stop recording there is a Spectacle stop button in the KDE system tray. The job in Shotcut should stop automatically at this point and the recorded file opens in Source but not always.
If something else this is an OBS Studio app launcher if obs is in your PATH. Otherwise, it opens a file dialog for you to choose an executable that it saves to Shotcut’s config file. Now, it is simply an app launcher for that tool.