This article will help you to take a screenshot on your mac or windows computer for sending to tech-support, use in presentations or anything else you might desire.

Mac

Mac users can press Cmd+Shift+3 to take a screenshot of their entire screen. It will be automatically saved as a .png (image) file on your desktop.

Cmd+Shift+4 will let you drag a box around only part of your screen and save it, again, on the desktop.
Filenames will be saved using the formula: "Screen Shot <current date> at <current time>.png".

You can use Cmd+Shift+5 to enter the Mac screenshot utility with more advanced features

See this Apple article for the full capabilities of screenshots on the mac.

Windows

Best Option: Press Win+Shift+S to open the quick-screenshot interface. It allows for various ways to take screenshots and saves them to the clipboard for use in other apps.

There is an older screenshot tool for Windows users called "Snipping Tool" that is still available in Windows 10. 

You can click your start button and search for it by typing: snipping

This tool will provide for all your screenshot needs, including saving, emailing and some simple annotating of your screen shots.

Alternatively, you can press PrtScn on the keyboard, open your favorite image editor (MS Paint, Photoshop, even Powerpoint) and paste the image there to save. This method will grab the full screen and relies on the image editor for cropping and other editing.