You do not have to ask someone for friendship. It is something given naturally and freely if a person likes you. By showing interest in others you will soon find yourself with a group of friends.
Well in blurtit first go to their profile go down till the end you will see a option add as a friend. Click on it. A Friendship request will be sent to them.
Go to their profile and hit add as a friend where their shout box is
Just go to that person's profile, click the add as a friend tab, and a request will be sent to them. You then need to wait for them to respond to your request