It is an optional four-rakat prayer that the Prophet ﷺ prayed frequently and advised the companions to pray, and its time is about 20 minutes after sunrise and 15 minutes before Zuhr.
The minimum number that has been reported in the case of Duha prayer is two rakats. Muslim (720) narrated from the hadith of Abu Dharr (may Allah be pleased with him) that the Prophet (blessings and peace of Allah be upon him) said: “…and two rakats offered in the forenoon (Duha) will suffice for that.”
The ruling is that Duha prayer is a sunnah mu’akkadah (confirmed Sunnah), which entails massive rewards and blessings if established, but there is no sin on the one who leaves it.
Prophet Muhammad (S.A.W.) said:
“Charity is required from every part of your body daily. Every saying of ‘Glory be to Allah’ is charity. Every saying of ‘Praise be to Allah’ is charity. Every saying of ‘There is no God but Allah’ is charity. Every saying of ‘Allah is the Greatest’ is charity. Ordering the good is charity. Eradicating the evil is charity. And what suffices for that (as a charity) are the two rak’at of duha.” This is related by Ahmad, Muslim, and Abu Dawud.
Dua
Allah Almighty knows best.