Hi Suresh,
You can use Box 14 to display any Company provided benefits related to Stock plans or other plans, anything paid as benefit outside system and entered in SAP system may be using IT0221 as for reporting purpose and also any voluntary taxes like California VDI /448 tax in Box 14.
Also, you can display any supporting wages that are linked to box 1 but are not part of box 1 here like lease value of vehicle provided to employee, etc.
Hope this helps.
Thanks,
Ameet