Diwali is observed by Jains as Mahavir Nirvan Diwas, commemorating Mahavir Swami attaining Moksha. On this day, many Jains focus their devotion on Mahavir and his teachings and engage in prayer, reflection, and dhyana.

Ways you can perform Mahavir-focused jaap on Diwali (simple and traditional):

• Chant Navkar Mantra (the fundamental Jain prayer) or a short prayer dedicated to Mahavir. If you’re unsure of the exact words, you can repeat the general idea of bowing to the Tirthankaras and seeking purity and right conduct.
• Visit a Jain temple or a home shrine, offer flowers or sesame seeds/food as a symbolic devotion, and listen to or read stories about Mahavir’s life and teachings.
• Reflect on Mahavir’s core values: non-violence (ahimsa), truth (satya), non-stealing (asteya), celibacy (brahmacharya), and non-possessiveness (aparigraha). Try to recall or recite a short verse or meditation that reinforces these values.
• Practice quietness and compassion for living beings for the day, aligning thoughts and actions with Mahavir’s teachings.

If you’d like, I can provide the exact text of a Mahavir-focused prayer or the Navkar Mantra in a Jain-authentic format. I can also point you to a page on JainKnowledge.com that has the traditional wording.