Simple Screen Recorder is a simple GUI program that can be used to capture your desktop and write it to a video file. It has a wizard interface that takes you through a wizard to start every recording session. If you have multiple screens, it allows you record both, either or the screen with activity. You can choose the framerate you want and the output video file format you wish.
I typically use SimpleScreenRecorder to record a short screen session to share a GUI operation or a long screen session to log and analyse my activity.
$ sudo apt install simplescreenrecorder
Tried with: Ubuntu 18.04