Al-jawab billahi at-taufeeq (the answer with Allah’s guidance)
The rightly guided Caliph Umar ibnul khattab (RA) revived the Sunnah of having the prayer of 20 rakat Tarawih with congregation in every night of Ramadan and the completion of the entire Quraan began only during the khilaafat of hazrat Umar (RA). All the Sahaabah present had agreed upon this practice. From then onwards including the Khilafah of both Hazrat Uthmaan and Hazrat Ali (RA) upto this day the Muslim Ummah (at large) has followed this practice.
And Only Allah Ta’ala Knows Best.