You must enter the Roth IRA contribution(s), then, when TurboTax indicates that there is an excess contribution, indicate the amount of excess contribution returned (not the gain/loss-adjusted amount distributed). This will cause TurboTax to prompt for an explanation statement describing the return of contribution.
If there was any gain distributed with the returned contribution you must also enter the made-up 2019 Form 1099-R described by CherylW (in that case a 2017 Form 1099-R for a 2016 contribution returned in 2017), except for one error in that answer: Both codes P and J must be used and, if over age 59½ at the time of the return of excess contribution, claim an Other reason exception to the early-distribution penalty on the taxable earnings entered in box 2a.
