It is recited frequently while walking, sitting, or traveling between holy sites.
It is Sunnah (the practice of the Prophet) for men to recite it loudly and for women to recite it softly.
Islamic tradition suggests that when a pilgrim recites this prayer, everything around them—stones, trees, and the earth—joins in the remembrance. 3. Ritual Rules (How and When to Recite)
It is seen as a response to the eternal invitation sent by Prophet Ibrahim to all of humanity to perform pilgrimage.
By repeating "Lebbeyk" (Here I am), pilgrims signify that they are leaving worldly concerns behind to focus entirely on their Creator.
لَبَّيْكَ اللَّهُمَّ لَبَّيْكَ، لَبَّيْكَ لَا شَرِيكَ لَكَ لَبَّيْكَ، إِنَّ الْحَمْدَ وَالنِّعْمَةَ لَكَ وَالْمُلْكَ، لَا شَرِيكَ لَكَ