Who is ALLAH ?
Allah - He is the Creator

If you asked them, "Who created the heavens and earth and subjected the sun and the moon?" they would surely say, " Allah ." Then how are they deluded? (Alquran 29:61)
Provider
Allah extends provision for whom He wills of His servants and restricts for him. Indeed Allah is, of all things, Knowing. (Alquran29:62)
And if you asked them, "Who sends down rain from the sky and gives life thereby to the earth after its lifelessness?" they would surely say " Allah ." Say, "Praise to Allah "; but most of them do not reason.
(Alquran 29:63)
Your god is only Allah , except for whom there is no deity. He has encompassed all things in knowledge." (Alquran 20:98)
Some Names of Allah
Allah - there is no deity except Him. To Him belong the best names. (Alquran 20:8)
He is Allah , other than whom there is no deity, the Sovereign, the Pure, the Perfection, the Bestower of Faith, the Overseer, the Exalted in Might, the Compeller, the Superior. Exalted is Allah above whatever they associate with Him. (Alquran 59:23)
Ever Living
Allah - there is no deity except Him, the Ever-Living, the Sustainer of existence. (Alquran 3:2)
Allah witnesses that there is no deity except Him, and [so do] the angels and those of knowledge - [that He is] maintaining [creation] in justice. There is no deity except Him, the Exalted in Might, the Wise. (Alquran 3:18)
Say, [O Muhammad], "If there had been with Him [other] gods, as they say, then they [each] would have sought to the Owner of the Throne a way." (Alquran 17:42)