If you received a W-2c -- the "corrected" W-2 form -- you can ignore the W-2 and input only the W-2c, since that takes precedence. You'll enter it on the same W-2 screen that you would enter a regular W-2.
Once you've entered the W-2c, you'll be shown a screen with a list of uncommon situations, where you'll check the box for corrected W-2.
