Tawaf al-Ifadah is obligatory, and through this Tawaf the Hajj is completed. Tawaf al-Ifadah is also called Tawaf al-Ziyarah. Many also call it the Tawaf of Hajj. Without it, the Hajj will not be valid. Allah Most High says,
﴿ ثُمَّ لۡيَقۡضُواْ تَفَثَهُمۡ وَلۡيُوفُواْ نُذُورَهُمۡ وَلۡيَطَّوَّفُواْ بِٱلۡبَيۡتِ ٱلۡعَتِيقِ ٢٩ ﴾ [الحج: ٢٩]
‘Then let them cleanse themselves, fulfil their vows, and circumambulate the Ancient House.’[1]
[1]. Al-Hajj: 29.