Dear Shilpi,
Before having code of conduct, first check whether you have standing orders approved by the labour office. Though the code of conduct is far more than the standing orders, basics need to be given priority.
Conduct of conduct includes business and workplace etiquette, communication protocol, meeting manners and so on. In many companies, the code of conduct is included in the employee handbook. Therefore, designing a separate policy is not recommended.
Going further, it is not just a question of having a policy or inclusion of code of conduct in the employee handbook, you need to train the employees on implementation. Otherwise, there could be mismatch in the policy on paper and actual work practices.
For getting the employee handbooks, you may search this forum.
Thanks,
Dinesh Divekar