Mu'adha asked 'A'isha (Allah be pleased with her) how many rak'ahs Allah's Messenger (ﷺ) prayed at the forenoon prayer. She replied: Four rak'ahs, but sometimes more as he pleased.
Hadith Referenceصحيح مسلم / كتاب صلاة المسافرين وقصرها / 719
Mua'ada 'Adawiyya reported 'A'isha as saying: The Messenger of Allah (ﷺ) used to observe four rak'ahs in the forenoon prayer and he sometimes observed more as Allah pleased.
Hadith Referenceصحيح مسلم / كتاب صلاة المسافرين وقصرها / 719
´Mu’adhah Al-‘Adawiyyah said:` “I asked ‘Aishah: ‘Did the Prophet (ﷺ) pray Duha?’ She said: ‘Yes; four (Rak’ah) and he would add whatever Allah willed.’”
Maulana Ataullah Sajid
Benefits and Issues: ➊ From this it is understood that, besides Umm Hani radi Allahu anha, Aisha radi Allahu anha also saw the Prophet sallallahu alayhi wa sallam performing the Duha (forenoon) prayer. And a legal ruling (mas’alah) is established even from the narration of a single Companion radi Allahu anhu.
➋ The Duha prayer can be performed with less or more than eight units (rak‘ahs); its minimum is two units (rak‘ahs). (Sahih Muslim, Salat al-Musafirin, Chapter: Recommendation of Salat al-Duha, Hadith: 720, 721) On the occasion of the Conquest of Makkah, the Prophet sallallahu alayhi wa sallam performed eight units (rak‘ahs). In Hadith 1379, there is a reference to this very incident.
Source: Commentary on Sunan Ibn Mājah by Mawlānā ‘Atā’ullāh Sājid, Page: 1381