How do I enter the information from a Form 1099-R that was issued to reflect the conversion of pre-tax 401(k) contributions to a Roth 401(k)?

This is an In-plan Roth Rollover (IRR).  IRRs are reported with code G in box 7 of the Form 1099-R and the taxable appears in box 2a.  Enter the Form 1099-R exactly as received under Wages & Income -> Retirement Plans and Social Security -> IRA, 401(k), Pension Plan Withdrawals (1099-R).  In the follow up, answer Yes to the question asking if the distribution was rolled over to a Roth 401(k) or a Roth 403(b).  The taxable amount of the IRR (often the entire amount) will appear on Form 1040 line 16b or Form 1040A line 12b and the word ROLLOVER will appear next to the line.