One of the optional prayers is Salatul Duha.
Abu Dharr Radhiallahu ‘anhu reported: The Prophet (Sallallaahu alayhi was sallam) said,
“In the morning, charity is due on every joint of the body of every one of you. Every utterance of Allah’s Glorification (i.e., saying Subhan Allah) is an act of charity, every utterance of His Praise (i.e., saying Al-hamdu lillah) is an act of charity, every utterance of declaration of His Greatness (i.e., saying La ilaha ill Allah) is an act of charity, and every utterance of declaration of His Power (i.e. saying Allah Akbar); and enjoining M`aruf (good) is an act of charity, and forbidding Munkar (evil) is an act of charity, and two Rak`ats of Doha Prayers which one performs in the Forenoon is equal to all this (in reward).”
Recorded by Muslim
Its time is from about 20 minutes after the sunrise till about 45 / 30 mins before Salatul Dhuhr.
The time for Duha prayer is from when the sun has risen to the height of a spear, which is fifteen or twenty minutes after sunrise, until just before the sun passes its zenith (and the zenith is when the time for Zuhr prayer begins). What is meant by just before the sun passes its zenith is ten to fifteen minutes before it reaches the zenith, i.e. before the time when it is forbidden to pray begins. End quote. Majmoo’ Fataawa al-Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him), (14/306).
Ibn Muflih (may Allaah have mercy on him) said: The time for (Duha) is from when the time when it is forbidden to prays ends, until the sun reaches its zenith. What is meant – and Allaah knows best – is just before the sun passes its zenith, because it is forbidden to pray at that time. End quote from al-Furoo’ (1/5670)