Should the Dhuha prayer be prolonged like the late night prayer or should it be light?
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
The Sunnah with regards to the late night prayer is to be rather long and the Dhuha (i.e. forenoon) prayer is to be light, just like the Prophet, sallallaahu ‘alayhi wa sallam, used to perform it. Umm Haani’ said, "The Prophet, sallallaahu ‘alayhi wa sallam, came to my house on the day of the Conquest of Makkah, took a bath and offered eight Rak‘ahs (for the Dhuha prayer). I had never seen the Prophet, sallallaahu ‘alayhi wa sallam, offering such a light prayer but he performed the bowings and prostrations perfectly." [Al-Bukhari]
You can search for fatwa through many choices