Updated for 7.0
Click on the Settings icon (the gear) located to the right side of the search bar. This will take you here:
In the horizontal navigation bar, select Users. This will provide drop-down options.
From the drop-down options, select Additional Fields. This will take you here:
To edit additional fields, click the button with the pencil icon located to the right of the desired field.
Follow the prompts to edit the desired fields.
When done, click the Save button located at the bottom of the pop-up window to save changes.