require Mac OS 10.13 bootable os download link

..huhtamakiajay:

There are instructions on 'how to create a bootable

installer for macOS' versions in this support article.

"You can use an external drive or secondary volume as a start-

up disk from which to install the Mac operating system."

"These advanced steps are primarily for system administrators

and others who are familiar with the command line.  You don't

need a bootable installer to upgrade macOS or reinstall macOS,

but it can be useful when you want to install on multiple comp-

uters without downloading the installer each time."

• How to create a bootable installer for macOS - Apple Support

https://support.apple.com/en-us/HT201372

Links to use for the creation of said bootable installers, are

in each of the named systems; & visible with mouse-over.

Advice to one so inclined: read through the article &

understand you may not actually need one of these.

Instructions in another form, lead one past same down-

loads for each of those, in other linked support page:

• How to get old versions of macOS - Apple Support

https://support.apple.com/en-us/HT211683

To perform this action will require booting from a Bootable Installer. 

This will have to be performed from a Qualifying Computer to run the version of macOS to be made on the Bootable Installer. Example : Bootable Installer of High Sierra would have to be done on a computer that Qualifies to run High Sierra .

All this must be performed Only on an Apple Computer.

If the Apple Computer does not Qualify to run High Sierra because it it too OLD or if the Apple Computer is too NEW - this computer can not be used to perform it action.