Duha, sometimes called the mid-morning or 'forenoon' prayer, is a voluntary two-or-more rak'ah prayer performed after the sun has fully risen above the horizon — roughly fifteen to twenty minutes after sunrise — until shortly before the sun reaches its zenith at midday. The Prophet Muhammad linked it to the idea that every joint of the body owes a form of daily charity, explaining that saying 'Subhan Allah,' enjoining good, and forbidding wrong all count as such charity, 'and two rak'ahs which one prays in the forenoon will suffice for all that' (Sahih Muslim 720). In other words, Duha functions as an easy, accessible act of gratitude that covers the body's daily 'debt' of thankfulness. Scholars record the Prophet praying anywhere from two to eight rak'ahs for Duha, and there is no single fixed number; most agree two is sufficient, while more is better. It is not obligatory and is especially recommended for those who wish to start or punctuate their workday with a short act of worship and remembrance of Allah.
Q&A · Prayer
What is Duha prayer, and when is it prayed?
References
Sahih Muslim 720
Informational, not a personal fatwa. Consult a qualified scholar for rulings on your situation.