Share Specific Part Of Screen

I can't screenshare properly because I have a 49 Inch Monitor. For Anyone viewing my screen without a 49 inch monitor will see a very stretched, very ugly, and impossible to see view... Please Make it so Discord Automatically puts up some sort of 1920 x 1080 resolution screensharing box that will only screenshare exactly what's inside of it so people won't have to see such a stretched screen.