For someone to take out A Life Insurance policy for you they will have to get your written permission and also likely have to have you see a doctor for a medical examination before the Life Insurance Policy will be issued.
Someone else can take out A Life Insurance Policy on you but they must have your permission to take out the Life Insurance Policy on you so they cannot get Life Insurance on you without you knowing about it.
The person who's taking out Life Insurance on you has to have your written consent before doing so.