When you enter a Jain mandir, the best and most universal prayer to chant is the Navkār (Namokār) Mantra.

You can softly chant:

णमो अरिहंताणं। णमो सिद्धाणं। णमो आयरियाणं। णमो उवज्झायाणं। णमो लोए सव्वसाहूणं॥

Simple meaning:

• I bow to the Arihants (perfect enlightened beings).
• I bow to the Siddhas (liberated souls).
• I bow to the Āchāryas (spiritual heads).
• I bow to the Upādhyāyas (spiritual teachers).
• I bow to all Sādhus and Sādhvīs (monks and nuns) in the world.

This mantra is accepted in both Digambar and Shvetambar traditions. It is the main prayer Jains chant on entering the temple, before doing darshan or pradikshina.

Very simple way to use it when you go to mandir:

1. At the entrance, think “Jai Jinendra” in your mind and feel respect.
2. Stand quietly facing the main idol and chant Navkār Mantra slowly 3, 5, or 9 times with bhāv (feeling).
3. Then do your darshan, pradikshina, and other stavans as per your family’s tradition.

You can read a very simple explanation of Navkar Mantra here