In a previous post I gave a quick introduction to OBS, if you are not familiar with OBS, I highly recommend checking it out. In this post, I’ll show you how you can easily annotate while recording or streaming with OBS.
Often while presenting we will use a pointer to bring attention to an area on a slide or a smart board/whiteboard to help illustrate a concept or idea and further engage our audience. In my quest to provide the same experience while using OBS for recorded and streaming demos I discovered there are several tools available that enable you to write and draw on your display capture device.
Epic Pen is a screen marker and desktop annotation tool with a simple interface. There is a free version with limited features but are adequate and also a paid pro version offering more features. It also includes handy screenshot functionality and supports custom hotkeys which is very convenient during video recording. To upgrade to the pro version is $25, a worthy investment.
Features include:


You might also want to checkout gInk its free and open source.
Have Fun!