Salaam could you please explain what is sunnah mu'akkadah and sunnah ghair mu'akkadah?
Sunnah mu’akkadah refers to any voluntary act of worship (such as the Eid prayer, or the two rakat after the maghrib prayer) which the Prophet continuously performed and almost never abandoned. These are not obligatory, but a person who abandons them is considered blameworthy.
As for the ghair mu’akkadah ones, they are those which the Prophet sometimes performed and sometimes abandoned, such as two rakat before the Isha prayer.
The different schools of thought have different terminology and rulings regarding the precise nature of these acts of worship.