If I withdrew from my 401 what do I need

You need the 1099R from the financial institution that manages the retirement account.   Sometimes you can import it or you might have to go to their web site to get it.   

To enter your retirement income, Go to  Federal> Wages and Income>Retirement Plans and Social Security>IRA  401 k) Pension Plan Withdrawals to enter your 1099R.

If your bank or financial institution is not on the drop down list, click the words “I’ll type it in myself” and key in your information by hand.

See if your financial institution is on the Partner List - If not, you will have to enter the information manually.  

You should get a 1099R from the 401K plan.  Ask them for another copy .   Do they have your right address?  Maybe you can log into your 401K account and print off a copy of the 1099R.  Most places have it posted to download.