If your AGI is negative, after you click "Done with Deductions" at the bottom of the screen "Your 2018 Deductions & Credits," a couple of screens later it will ask you if you have an NOL for 2018. If you select Yes, the next screen will ask you whether or not you want to carry it back. If you elect not to carry it back, it will include the necessary election form in your return. I believe you will still be able to e-file.
You can also get to this topic in the interview by entering "nol elections, current year" in the Find box at the top right. When you type NOL, this will be one of the choices in the drop-down list.
No edition of TurboTax includes Form 1045. You can download the form and its instructions from the following links on the IRS web site. You have to do the calculations and fill out the form yourself. The form includes Schedules A and B. Form 1045 is not part of your tax return. It is filed separately.
Form 1045: http://www.irs.gov/pub/irs-pdf/f1045.pdf
Instructions: http://www.irs.gov/pub/irs-pdf/i1045.pdf
For example the software carried forward 100000 of NOL from 2017, when I elected NOT to carry back. This carryforward feeds in on line 21 of Schedule 1 of 1040 for 2018. This amount needs to be adjusted by the modified taxable income which only allows me to carryforward $60,000. I don't know where to make this modification so that only $40,000 of NOLS are used up and $60,000 carryforward to 2019. I went nol elections, current year, I answer Yes, I have an NOL for 2018, but then it moves on to retirement income, it doesn't ask me if I want to carry it back.