Camtasia is a software that allows you to record your screen (= screencasting) and edit any kind of video material. As you might have seen in the FitFOL online tutorials and video messages, the software makes the combination of text, pictures, annotations, video and audio possible. When casting your screen, you can decide to record yourself on camera and/ or audio alsongside the things you show on the screen. While editing, you can combine different materials and record audio once you are done.
Concerning teaching content, you can create instructor video messages, instruction tutorials, slideshows with instructor narratives, summaries, video feedback and many things more.
To learn more and maybe do a trial, visit the company page here: https://www.techsmith.com/video-editor.html
Note that if you are interested in the product, education pricing applies for you.