This is a common question but it is invalid. The God of the bible, the true living God, is an eternal being.

Definition of eternal: permanent, unending. Eternal, endless, everlasting, perpetual imply lasting or going on without ceasing. That which is eternal is, by its nature, without beginning or end

Here is some scripture to that show that God is eternal:

The eternal God is a dwelling place
And underneath are the everlasting arms Deut 33:27

Do you not know? Have you not heard?
The Everlasting God, the LORD, the Creator of the ends of the earth
Does not become weary or tired
His understanding is inscrutable. Isaiah 40:28

It has seemed good to me to declare the signs and wonders which the Most High God has done for me.
“How great are His signs
And how mighty are His wonders!
His kingdom is an everlasting kingdom
And His dominion is from generation to generation. Daniel 4:2-3

This means that God has always existed, He had no beginning and will have no end. Now, we can see that to ask who created God makes no sense.