I inadvertently selected that I do not have an e-filing pin from the IRS but I received a pin in the mail today.. How do I go back and add the e-filing pin number?

Here are two ways to navigate to the section to enter the 6 digit IP PIN: 

1. Log in and open your return ("Take me to my return") 
2. Once the return is open, then go to the Federal Taxes tab. 
3. Subtab Other Tax Situations 
4. Scroll down to Other Return Info. 
5. Choose Identity Protection PIN and Start (or Revisit.) 
6. Next screen asks:  "Did you or any of your dependents get an IP PIN from the IRS for this year's taxes?" 

Or another way: 

1. Open your return if not already open.  ("Take me to my return.") 
2. Once the return is open, click at the top on MY ACCOUNT, then choose TOOLS. 
3. In the Tools window choose TOPIC SEARCH. 
4. Enter IP PIN without quotes. 
5. In the selection list highlight IP PIN and click GO. 
6. Next screen asks:  "Did you or any of your dependents get an IP PIN from the IRS for this year's taxes?"