Per IRS Instructions for Form 1120-S, page 22:
Schedule K-1 shows each shareholder's separate share. Attach a copy of each Schedule K-1 to the Form 1120-S filed with the IRS. Keep a copy for the corporation's records and give each shareholder a copy.
Give each shareholder a copy of the Shareholder's Instructions for Schedule K-1 (Form 1120-S) or specific instructions for each item reported on the shareholder's Schedule K-1.
Note that any link in the information above is updated each year automatically and will take you to the most recent version of the webpage or document at the time it is accessed.