The previous answers pertain to Form 1040 for years prior to 2018. For a 2018 or 2019 Form 1040, refer to lines 4a/b instead of lines 15a/b.
A rollover from a 401(k) should appear on 2019 Form 1040 line 4c/d. If the rollover is nontaxable it should be included on line 4c and not on line 4d, If the rollover is taxable because it was from a traditional account in a 401(k) to a Roth IRA, the taxable amount should appear on line 4d. With regard to rollovers, only the taxable amount of a rollover to a Roth account adds to you AGI.
Distributions from a 401(k) are to be entered into TurboTax by entering the From 1099-R reporting the distribution from the 401(k) and answering the follow-up questions.
