You'll receive a Form 1099-R Distributions From Pensions, Annuities, Retirement or Profit-Sharing Plans, IRAs, Insurance Contracts, etc. from the payer of your 401(k) distribution. A copy of that form is also sent to the IRS.
To report the 401(k) distribution in your Online TaxAct return:
For additional information, go to IRS Publication 575 Pension and Annuity Income.