How to create a bootable installer for macOS High Sierra

Below steps should be performed as Mac Mac Admin user.

1) First Step before upgrade or Erase install Please back up all your data.
2) Check for you Mac that is compatible with the Mac OS : https://support.apple.com/en-in/HT201686
3) Download macOS from the App Store
4) When the macOS installer opens, quit it without continuing installation.
5) connect the USB flash drive or other volume that will be used as the bootable installer. Make sure that it has at least 12GB or more available storage.
6) Open Terminal, which is in the Utilities folder of your Applications folder or spotlight Terminal search to open.
7) open Disk utility and Erase the Disk in HFS format volume name should be MyVolume.
8) Type or Paste the following commands in Terminal.

sudo /Applications/Install\ macOS\ High\Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install\ macOS\ High\Sierra.app

9) Enter the Mac Admin password

10) Terminal will confirm for Eraising the volume Type Y and confirm with password if asked.

and the process will start.