There are 3 things Fardh (obligatory) in Hajj:
2. Stay in Arafaat (Wuquf-e-Arafaat)
The Wajib articles of Hajj are 6:
1. Spending the night which comes after the 9th of Dhul Hijjah in Muzdalifa.
2 . Doing Rami i.e. throwing stones at Jamraat
3. Performing Sa'ee between Safa and Marwah.
4. Shaving the head or i.e. cutting the hair (Halq or Qasr)
5. Performing the Tawaf Sadr i.e. performing Tawaf Wada'a at the time of leaving, which is also called as Tawaf Wada'a (Farewell Tawaf).