Islam and Christianity are two recognized religion in China. Falun Gong and Scientology are not.

The Quran and Bible books can be purchased in bookstores and online shops, like Aliexpress, in China.

Proselytizing is only permitted in private settings or within registered houses of worship. Proselytization in public, in unregistered churches or temples, or by foreigners(before, there were many foreign English teachers doing proselytizing works in school classrooms) is prohibited. Members of the officially atheist Communist Party are strongly discouraged from holding religious faith.

and,

you cannot convert somebody under the age of 18.