Another way that doesn't require additional software is to use the following commands that are built into Windows:

ALT-PRT SCR takes a screen shot of the active window
PRT SCR takes a screen shot of the entire display

In both cases you can paste the resulting screen capture into a graphics program to crop or edit as desired.

If you bring it into WORD or EXCEL you can non-destructively resize it and add all sorts of text boxes, callouts, lines, arrows etc to highlight whatever it is that you want to convey to your audience. One you have it notated the way you want, you can ALT-PRT SCR and pop it into a graphics program and save it to a file tha can be uploaded to the web

https://www.dropbox.com/sh/ey71h8ep047758h/AAC12jNM0Hz9Q8zsh5iDeqNHa?dl=0