Yes, it is necessary. I should contain photo, name, designation, employee ID No., department/place of posting, blood group and contact no. with logo of the employer co. Many establishment incorporate these details in their magnetic access card itself. This practice ensure only bonafide employees and other authorised persons only will have access to the premises/work places. If the establishment is very small and employs only handful of persons there won't be such needs. It shall be the policy of the employer firm.