Imaam Ibn Qudaamah Al-Maqdisi rahimahullaah said:
know verily oh reader, that the Supererogatory prayers are divided into the following three categories:
♦ Assunan.
These are the supererogatory prayers, which the Messenger salallaahu alayhi wasallam persisted in offering them like the nawaafil after the obligatory prayers, Witr and Adduha.
♦ Al-Mustahabbat.
These are the supererogatory prayers about which there are an authentic AHaadith that shows its virtues and recommends offering it but there is no indication in the Hadith that illustrates that the Messenger of Allah salallaahu alayhi wasallam persisted in offering them like making nawaafil on getting to one’s destination or when leaving the house.
♦ Attatawa’at.
These are the optional prayers, which there is no authentic Hadith that recommends them but the servant of Allah offers it as nawaafil.
All these three classifications are called Annawaafil.
The virtues of these prayers and its categories are dealt with in detail in the books of Fiqh.
Allaahu A’alam
Baarakallaahu feekum