Simultaneously depressing the keyboard keys Ctrl+Prt Sc will take a screenshot of exactly what is on your screen.The Prt Sc ,PRINT SCREEN,key is probably near top rt hand corner of keyboard.That action will copy your screen image to the clipboard.Then paste into Paint app or similar,Photoshop perhaps.Then you can crop out / erase the unwanted parts of the screenshot. Then SaveAs 24-bit Bitmap,or whatever file format is required by the recipient. Bit of a bodge up though,but a handy tip if u don't already know it.
I've just tried it on my old half ruined by Windows 10 PC, and it does still work in Win 10,unlike the operating system itself.Buggy is a GROSS UNDERSTATEMENT ! Linux PC / Chromebook better by lightyears,not miles.
Or if you're a stickler for correctness, ie the SI system, Kilometres,or more specifically,1 Parsec. Metric (SI) units: 3.0857×1016 m; ~31 petametres