Drawing on a screen

This is how I do it. I connect a graphics tablet to my computer using usb that comes with the tablet. The I run my powerpoint slide. I may have a blank slide with my preferred colour (black). When runing the PowerPoint slide, go to the "pen" icon next to the navigation at the bottom left corner. Click it and the pen appears as a dot. You may choose the colour of the pen at this point. Keeping my eye on the screen and guided by the dot on the screen, I can write on the scrren as I would do on papre using a pen. When I'm done writing, I simply navigate to the next slide. But when you want to exit the slide show, you will be promted to save this inking of the slide. You may discard it but it will of course appear in your screen capture. If you're using camtasia, you can hold "ctrl + shift+ D". A pen appears and you can write on the screen. You do not need to use PowerPoint. Hope this helps.