Is it permissible to combine and shorten prayers for a traveler, and when do shortening and combining begin, and what are the rulings on prayer for a traveler regarding determining the Qibla, performing Tayammum, and praying in public places?

Travel is one of the excuses that permit jama' (combining prayers). The distance that allows qasr (shortening prayers) and jama' is four burd (approximately 83 kilometers), according to the majority of scholars. A traveler is permitted to combine and shorten prayers after departing from the houses of their town. As for before leaving, one should not combine prayers unless they know that they will not be able to perform the second prayer within its time, or if it would be difficult for them to do so. In such a case, it is permissible for them to combine prayers while performing them fully (not shortened) in their town. This is a strong opinion that permits combining prayers due to a general need.