It varies from person to person. Most people can't say their phone number, but now girls in society are bold and reckless. If they don't think it will affect them, they will tell them. That person must be the opposite sex. Of course, girls who have boyfriends should not tell them again, unless they have a bad relationship with their boyfriends, no matter whether that person is bad to themselves or not, even if they just make friends, boyfriends may not like this way of meeting.