After the Farz and Sunnat of Magrib, performance of the minimum of 6 to a maximum of 20 rakaats is called Salatul Awwabeen.
1. Awwaabeen is the six Rakaats of Salaat after the Maghrib Salaat. It is established from the Hadith.
Rasulullah [sallallallaahu Alayhi Wasallam] mentioned, "Whoever performs 6 Rakaats after Maghrib Salaat will earn the reward of 12 years of Nafl Ibaadah." (Tirmidhi)
and Allah Ta'ala Knows Best
Mufti Ebrahim Desai
2. According to the soundest opinion, the Salat al-Awwabin (prayer of the oft-repentant) is 6 rakats, prayed after the Maghrib prayer in sets of two. It is best to do this after the 2 confirmed sunna rakats, though it is also valid to consider those 2 rakats from the 6.