In China, household registration management is strict and rigorous. The head of the household is usually the oldest male member of the family. After grandma's death, if there are other male members in the family, the oldest one will become the new head of the household. If there are no other male members in the family, the identity of the head of the household will be inherited by the female members of the family. In this case, the granddaughter can't directly inherit the identity of the head of household, and she needs to transfer her household registration to her own name through application, or register in registered permanent residence through other means.
The specific situation may be different due to different regions and policies. It is recommended that you consult the local household registration management department to understand the specific household registration policies and handling procedures.