Paushadh (paushad/posadh) is a lay Jain vow where a householder temporarily practices monastic-like disciplines to varishak samvar (stop new karmas) and nirjara (burn old karmas). Here’s what is typically required and observed:

• Sankalp (vow): Take a formal Paushadh vow in front of a guru or in front of Jina images/scriptures. The vow centers on living like a monk for a set time, with strict self‑control.
• Upashraya or clean space: Stay in a designated quiet place or upashraya/derasar, kept clean and simple, away from ordinary household distractions.
• Restraint in conduct:

- Very limited or no speaking; observe silence as much as possible. - Complete celibacy (brahmacharya) for the period. - Avoid business, travel, entertaining, adornment, and perfumes.

• Diet and daily routine:

- Often a fast or a very simple diet (one meal, or a strict day-long routine) before sunset; water may be permitted if clean. - Regular dharma activities: samayik (meditation on time), pratikraman (repentance), svadhyaya (scripture study), stavan, prarthana; and cleansing of the place where one sits/walks to avoid himsa. - Often include danda (humble conduct) and minimal possessions; sleep on a simple floor or mat.

• Pratikraman and visarjan: End with pratikraman and a proper visarjan (concluding the vow) once the period ends.
• Duration and varieties: Paushadh can be observed for short periods (e.g., a day or a night) or longer, and there are variations (e.g., ek‑paushad, be‑paushad, or multi‑day observances) depending on tradition and local maryada.
• Purpose: Strengthens the tenets of the householder's life, cultivates aparigraha (non-attachment), and accelerates spiritual progress.

Differences between Digambar and Shvetambar:

• Shvetambar tradition often uses terms like Posadh and emphasizes multiple samayiks and both morning/evening pratikraman; there are variant lengths and prakars in practice.
• Digambar tradition describes Paushadh as a stricter, monk‑like observance (Paushadha‑vrata) with emphasis on austerity, limited movement, and more internal focus.

You can read more about Paushad here