Why did Allah ﷻ create human beings?

The key to understanding purpose of human existence lies in following verse of the Quran: “And I have not created the jinn and men to any end other than that they may [know and] worship Me. No sustenance do I ever demand of them, nor do I demand that they feed Me: for, verily, God Himself is the Provider of all sustenance, the Lord of all might, the Eternal!” Asad in his Message of the Quran explains the meaning of this verse: “…the innermost purpose of the creation of all rational beings is their cognition of the existence of God and, hence, their conscious willingness to conform their own existence to whatever they may perceive of His will and plan: and it is this twofold concept of cognition (ma'arifah) and willingness that gives the deepest meaning to what the Qur’an describes as "worship” (Ibad'ah). This spiritual call does not arise from any supposed "need" - on the part of the Creator, who is self-sufficient and infinite in His power, but is designed as an instrument for the inner development of the worshiper, who, by the act of his conscious self-surrender to the all-pervading Creative Will, may hope to come closer to an understanding of that Will and, thus, closer to God Himself.”

In a hadith-e-qudsi Allah ﷻ said: “I was a hidden treasure; then I wished to become known. Then I created the creation, so that I may be known.” A hidden treasure is worth  struggling and seeking, for when discovered gives abundant joy and happiness and the state of inner, everlasting joy and happiness that humankind seeks is achievable through inner development, only possible as a result of unconditional obedience and wholehearted acceptance of Allah’s will or 'Self-Surrender' called Islam.