Specialization code and Xbox Live Family Plan

I have a family plan for live and I’m wondering if each email address on the family gets a code or if only the primary account does? If it’s only the primary account how do the other people on the family plan get a code?

Please use this thread to discuss the Specializations email topic:

https://forums.halowaypoint.com/yaf_postst148869_Halo-4-Specializations-Email.aspx

Please do not post private information (email addresses, etc.)

Thanks. This is my first time posting here.