Do you want to take screenshots on a Mac, but without shadow around the window? Then you can disable this by using a terminal command. Since macOS Mojave you have to use a different command than under macOS High Sierra (more info).
Disable screenshot shadows on a Mac
defaults write com.apple.screencapture disable-shadow -bool true
To make the command take effect, you need to restart the System UI server:
killall SystemUIServer
Revert to the default setting (screenshots including shadows), To make the command take effect, you also need to restart the System UI server!
defaults write com.apple.screencapture disable-shadow -bool false
