Tawaf-e-Ziyarat (also called Tawaf al-Ifadah) is one of the essential pillars of Hajj.
It is performed after returning from Mina, starting from the 10th of Dhul-Hijjah onwards.
Without performing Tawaf-e-Ziyarat, Hajj remains incomplete, which is why most scholars consider it Farz (an absolute obligation).
The Quran (Surah Al-Hajj: 29) refers to it as an obligatory act: "Then let them perform their prescribed duties and circumambulate the Ancient House (Kaaba)."