The pillars (obligatory acts) of ‘Umrah are three:
1. Entering into ihram with the intention in the heart.
2. Performing tawaf of the Baytullah.
3. Performing sa‘i between Safa and Marwah.
And the obligatory acts of ‘Umrah are two:
1. Entering into ihram from the miqat.
2. Shortening the hair of the head.
All other acts are Sunnah.
Hajj, ‘Umrah, and Visiting Madinah in the Light of the Qur’an and Hadith — Shaykh Muhammad ibn Salih al-‘Uthaymin (may Allah have mercy on him)