I found out that i have both my 1098-E forms (2018-19) which i previously thought i didn't but my returns were already accepted. Can i use them for next years returns?

[fermfdzjr96]

Like when i begin filing next year can i use both my 2018 and 2019 1098-E forms to increase my returns?

[SusanY1]

No, you cannot use a prior year form on next year's return (or last year's on this year's).  You must deduct the interest paid in the year paid.

You can amend the return to include the amount that you forgot about, though, if it would result in an additional refund.  

After you receive your refund - in approximately three weeks (longer if you have an additional child tax credit or earned income tax credit), you will need to amend your tax return by filing Form 1040X.  To do this, you will log back into TurboTax and select the option "I need to amend my tax return."

You can find more detailed instructions on that process here: How to amend a tax return in TurboTax.