Its saying I may owe under payment for 2016 to enter my Delaware tax from 2015 I don't know what im supposed to put down

[Critter]

It is the line that says total tax ... line 8 of the DE tax form ... so look at your 2015 tax form to get that number ...

http://revenue.delaware.gov/services/current_pit/TY15_booklet_res.pdf

[jkfeathers]

Open your 2015 Delaware return.

It is the line that says exactly this: 8. TOTAL TAX - Add Lines 6 and 7 and enter here................ > 8 then have a box with an amount in it.

If you filed with TurboTax deluxe you will have a stored .PDF of 2015 to download. Hit Ctrl+F and type "Total tax" and hit enter a few times, looking for a match of what I have listed above.