IMPORTANT: You only need to provide 'FAMILY BOOKLET' if it's mentioned in "Country Specific Requirements"
Family Booklet is a legal civil document with information about members of a family. It can be used to prove your relationship with other family members. It’s used in many European and Asian countries. Other names for a family booklet include:
For Pakistani Nationals, It's a document called "Family Registration Certificate (FRC)" however it's not a mandatory document to be submitted because it's not mentioned in "Country Specific Requirements".
NOTE 1: It doesn't matter if SPR or PA apply for FRC by marriage, same document will be issued due to ONE and unique Family Number.
NOTE 2: FRC by birth (father as head of family) is not required in Spousal Sponsorship application.