How to create bootable installer

I'd like to factory reset my mac (which is running El Capitan 10.11.6), while also updating the operating system. Here's what I've done (i.e. steps from this website) in order to create a bootable installer:

Downloaded the Mojave installer from app store

used sudo /Applications/Install\ macOS\ Mojave.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

When I do this, I get the error message "To use this tool, you must download the macOS installer application on a Mac with 10.12.5 or later, or El Capitan 10.11.6. For more information, please see the following: https://support.apple.com/kb/HT201372"

How can I update the operating system while also doing a factory reset? Thanks in advance.

I think the documentation saying MacOS 10.11.6 is wrong as I can't figure how to run that as well. You may need to have a friend run the installer and send you the USB drive with bootable media or perhaps try one last time to reinstall 10.11.6 from this link:

• http://updates-http.cdn-apple.com/2019/cert/061-41424-20191024-218af9ec-cf50-4516-9011-228c78eda3d2/InstallMacOSX.dmg

Sometimes re-installing the same combo updater fixes edge cases or some bit rot / rare damage to existing files. Just because your OS says 10.11.6 doesn't mean everything is in perfect running order.