If you wanted to add someone to your existing policy, you have to check with the insurance company whether you will be able to add an unrelated person to your existing policy. In case of health insurance policies, many insurance companies do not accept or add a person who is not related to you to your existing insurance policy. Also, if you have taken the insurance policy through your employer, then the employers consent is essential for such an addition. Talk with your employer regarding the addition and get his consent. Only after his consent you can add the person to your health insurance policy. Speak with your insurance agent and get all the necessary details form him because the policies will be different with different insurance companies. You may need to fill up the form and pay the additional premium cost to add an unrelated person to your insurance policy.