how to create emails for students

As Scott suggested, you're attempting to herd cats (students) in field someone else controls (Gmail).

The normal way most schools do this is to setup their own domain, with students associated with the schools, domain... like...

john.smith@somewhere.edu

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Or, far more simple, just have students provide an existing email address.

Or, take Scott's suggestion about using Google's special Gsuite school setup for students.

or use microsoft for education A1 plan for students (free)
https://www.microsoft.com/en-ca/microsoft-365/academic/compare-office-365-education-plans?activetab=tab:primaryr1

I didn't know that was available David. That looks like a good option.

there also is google for education https://edu.google.com/?modal_active=none

The dogs on GSuite are similar to non profit in that you have to wait 2 weeks to be authorized
https://support.google.com/a/answer/134628
https://support.google.com/a/answer/2856827

Either GSuite or MS365 allow bulk uploading of accounts to add from a spreadsheet/csv.

Even as both are good choices, keep in mind that managing this could potentially be a lot more time than you expect if you are going to have a teacher handle this that is also managing their own classes.

@Scott, I just noticed the GSuite Education discounts.

This does seem like a good way to go.