To download and create a bootable USB drive for macOS High Sierra 10.13, follow these steps:
Download macOS High Sierra:
Go to the Mac App Store.Search for macOS High Sierra.
Click on the download button and let it download.
Prepare the USB Drive:
Insert a USB drive with at least 12 GB of free space.
Open Disk Utility (you can find it in Applications > Utilities).
Select your USB drive from the list on the left.
Click on the “Erase” tab.
Choose “Mac OS Extended (Journaled)” as the format and give it a name.
Click “Erase” to format the USB drive.
Create Bootable USB Drive:
Open Terminal (you can find it in Applications > Utilities).
Use the following command to create a bootable USB drive:
sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia –volume /Volumes/Untitled
Replace /Volumes/Untitled with the name of your formatted USB drive if it’s different.
Installation:
Once the process completes, you’ll have a bootable USB drive with macOS High Sierra.
Restart your Mac while holding the Option key.
Select the USB drive from the boot menu.
Follow the on-screen instructions to install macOS High Sierra on your Mac.
Remember to back up any important data on your Mac before proceeding with the installation.
If you are looking for a dmg file please follow this link bellow
https://archive.org/details/MacOSXHighSierra10.13
I hope you find this article helpful
