Directly send Screenshot without saving
You can also copy to clipboard with


command+control+shift+3 for the whole screen
command+control+shift+4 for a part of the screen
command+control+shift+4 followed by space for a single window


and then paste the screenshot in a messaging application. As far as I see Skype for Business does not allow images in the chat. So you will have to use email or some other alternatives.