Is there a separate iso file for Windows 1803 Education?
Unfortunately, Microsoft stopped releasing separate ISOs almost a year ago.
If you are deploying it with a KACE SDA, and using verison 6.0, there is a new setting that will let you automatically pick the version you want.
You will need to build a new Scripted install.
Or, you could use DISM with that ISO, and locate the INDEX ID of Education, and then follow this:
Replace the <Valyue> with the ID matching the Education selection in your ISO.