If you have already filed your return, you'll need to wait for your tax return to either be rejected or accepted, if it is rejected you can add your Form 1098-E, correct any other errors on the return and resubmit it. If it is accepted, you will need to amend your return to include the Form 1098-E.
Please be aware that Form 1040X will not be available to prepare in TurboTax until mid-February, but once it is available, you will be able to prepare and print your amended return so that you can mail it to the IRS. You can not e-file an amended return as this cannot be filed electronically. The form is only filed on paper, so it will need to be printed and filed by mail.
Please see the following TurboTax FAQ for instructions on how to amend your 2016 tax return, if necessary, in TurboTax.
https://ttlc.intuit.com/replies/3288565
I f you have not already filed your tax return please see instructions below:
To enter Student Loan interest reported on Form 1098-E in your
return, please see the following instructions: