Is this for a W-2 entry? You can access this section by taking the following steps: 

1.) Federal

2.) Wages and Income

3.) Wages and Salaries

4.) Click through the screens until you see Here's Your W-2 Info

5.) Click Edit next to the W-2 information you wish to update 

You will want to make sure that your W-2 entries match your W-2 Forms exactly, as the IRS also receives this information.