If you want to use “Jain” as your surname, you may do so as a family identity/name choice, but in Jain Dharma the surname itself is not what makes someone Jain—conduct, vows, and devotion to Ahimsa matter more.

A simple way to adopt it is:

1. Decide the spelling you want to use

Usually it is written as Jain.

1. Use it consistently in your documents

Start using it in school records, bank records, ID, and official forms where allowed.

1. Update legal records if needed

If you want it changed officially, do it according to your local legal process.

1. Use it respectfully as a heritage name

Many people choose “Jain” to reflect their family and religious identity.

From a Jain view, remember:

• The name is external.
• True Jain identity is shown through Ahimsa, Satya, Asteya, Brahmacharya, and Aparigraha.

If you wish, I can also help with a simple Jain-style name format or how to write it in official documents.