You can keep it simple, respectful, and Jain‑focused. Examples:

In English:

• “Michhami Dukkadam, and wishing you a spiritually uplifting Mahavir Janma Kalyanak.”
• “On Mahavir Janma Kalyanak, may we all follow Bhagwan Mahavir’s path of ahimsa, satya and aparigraha.”

In Hindi / simple:

• “Mahavir Janma Kalyanak ni anek‑anek shubhkaamnao.”
• “Bhagwan Mahavir na janma kalyanak par, sab jivo ne shanti ane samata male – aavi mangal kamna.”
• “Mahavir Jayanti par aapke jeevan me ahimsa, daya aur shanti badhti rahe.”

With a Jain touch, you can begin or end with Navkar‑based respect:

• “Namo Arihantanam. Mahavir Janma Kalyanak ni hardik badhai.”

If you want to read more about Mahavir Janma Kalyanak and its meaning, you can see this explanation here: