Mahavir Swami’s granddaughter is not name-listed in the core Jain scriptures. What is well-attested is that Mahavir had a daughter (Priyadarshana, also called Anojja in some texts) with his wife Yashoda. The traditions differ on whether Mahavir married at all (Digambar tradition says he remained celibate; Śvetāmbara tradition says he did marry and had a daughter). Because there isn’t a standard, widely accepted name for a granddaughter in the primary texts, the granddaughter’s name is not fixed in Jain literature.

• Śvetāmbara view: Mahavir married Yashoda and had a daughter named Priyadarshana (also Anojjā in some sources). It does not specify a granddaughter by a single well-known name in the mainstream texts.
• Digambar view: Mahavir did not marry, so there is no daughter or granddaughter in that tradition.

If you’d like, I can point you to simple summaries in Jain Knowledge that cover Mahavir’s family and the Śvetāmbara/Digambara differences.