I want to file for 1098-T but for 2018

What does that mean?

1. You never filed a 2018 tax return?
2. You want to amend a 2018 return?
3. You want to claim a 2018 1098-T on your 2019 return?

#3 is not allowed.

For #2, see  https://ttlc.intuit.com/questions/1894381-how-to-amend-change-or-correct-a-return-you-already-filed

For #1, you can no longer e-file or use TurboTax on line.  You can only do the current year with TurboTax (TT) online software.

You can still prepare 2016-2018 returns with TT download software.  You cannot e-file, but must print and mail. https://turbotax.intuit.com/personal-taxes/past-years-products/

Or you can get forms (for mailing) from the IRS. https://www.irs.gov/forms-pubs/prior-year

There's a new urban myth among college students that says they can get a $1000 from the government just for filing a tax form. For most of them, they simply aren't eligible. A full time unmarried student, under age 24, is only eligible for the refundable portion of the American Opportunity Credit if he supports himself by working. You cannot be supporting yourself on parental support, 529 plans or student loans & grants. You usually must have actually paid tuition, not had it paid by scholarships & grants.  It is usually best if the parent claims that credit. 

You cannot claim a credit if you are, or can be, claimed as a dependent by someone else.

For full rules,  See https://www.irs.gov/Individuals/AOTC