It is recommended to pray Duha, the least of which is two rak`ah, the best of which is eight, and the average of which is four or six, and encouragement to do so regularly Sahih Muslim 717 b

Translation

'Abdullah b. Shaqiq reported

I aksed 'A'isha whether the Messenger of Allah (ﷺ) used to observe the forenoon prayer. She said: No, except when he came back from a journey.

It is recommended to pray Duha, the least of which is two rak`ah, the best of which is eight, and the average of which is four or six, and encouragement to do so regularly — Sahih Muslim 717 b