You can use mac’s createinstallmedia command. The format to create a bootable USB is given below.
$ sudo /Applications/Install\ macOS\ Sierra.app/Contents/Resources/createinstallmedia --volume |YOUR-USB-DRIVE-PATH-HERE| --applicationpath |DOT-APP-FILE-MACOS|
In My system the command will be as follows:
$ sudo /Applications/Install\ macOS\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/ABHI\'S/ --applicationpath /Applications/Install\ macOS\ Sierra.app/
You can easily find the corresponding software path in your system, if you have a different OS that mentioned above.
For more details, visit:
https://support.apple.com/en-us/HT201372