Wikipedia
Upadhāna are the religious practices performed by Śrāvakas in Jainism.
Upadhana can be performed in three parts for 47 days 35 days and 28 days separately. During these days one must fast on one day and the second day one must do Ekasan, that is eating one meal in one place. It is called Nivi.
Every day one must recite the Rosary for 20 times saying the Namokar Mantra; one must also perform 100 Khamasaman [Kneeling with head touching the ground]; must also perform Kayotsarga saying the Logassa Sutra for 100 times and must also perform the Paushadh vrat etc.
Along with these, one must study some Jain Agamas.This austerity is not only severe but prolonged. A special austerity called Pratima must also be performed by a Śrāvaka to purify and perfect their life. In the Agama Shastras, 11 types of Pratima are mentioned.
(1) Samyaktva (2) Vrat. (3) Samayik (4) Paushadh (5) Niyam (6) Brahmacharya, (7) Sachitta Tyag (8) Uddhisht (9) Preshyarambha tyag (10) Arambha tyag (11) Shramanbhuth
This vow should be taken for one or a fixed number of days according to rules.