What are the conditions for shortening the prayer (qasr)? And when does the shortened prayer (qasr) end?

The prerequisites for shortening prayers are that the journey must be for an act of obedience or a permissible matter, and the travel distance must reach four burud (approximately 83 km). Shortening of prayers ends upon the traveler's arrival at their homeland, or a place where their lawfully wedded and consummated wife resides, or by intending to stay for four days or more. Shortening is restricted to the four-rakah prayers (Dhuhr, Asr, and Isha).