This question has bugged many an intelligent mind for ages, with religions across the world giving various answers involving various deities and methods of creation being accepted as the default until Darwin came in and threw mud into the soup.
I lean towards and advocate for the Biblical view of creation, which has been and will be criticised sharply for "claiming the world was made in six days." Note the quotation marks. As a result of this and many more arguments, some Christians have made various concessions ranging from theistic evolution to abandoning religion altogether, which is tragic for them and those who convinced them so. But that is none of my business.
Dearly beloved, we are gathered here today to learn what the Bible says is the amount of time it took for God to make the world.
Genesis one one says, "In the beginning, God created the heavens and the earth."
So there was a beginning, and not of everything because God is from eternity to eternity. As a result, we can call this the logical beginning of our history.
What happened, then, in this beginning?
God set up His throne and the earth and made a few servants called angels. The Bible does not say whether these events took place at the same time, and how long it took because that is not why it was written.
I included the angels here because Lucifer must have existed before Adam was made here, and his acts of treason in heaven must have taken some time to ferment, foment and execute - from planning to convincing a third of God's angels to go to war against the King of the universe. These events are found in order in Ezekiel 28:12-17 and Revelations 12:7-17 respectively.
So we have a sequence of events here: God setting up His tent and the earth and making His servants. The order is not specified. Moreover, we have a slight caveat: He1 made a 'blank' world and went His way. Genesis one two: "And the earth was without form and void, and darkness was upon the face of the deep." There was water, then.
Is there an answer for how long it took to "make" the earth? No. Why? How much effort do you think it would take God to create a rock with water on it?2
The important bit comes next. Over six days, by the word of His mouth, God brings to existence countless stars, animals and birds, fish and insects, even time, and then finishes by taking some mud and making us. He therefore gives the earth its "form".
Something I find interesting here is He makes one or two things today and goes until tomorrow to do one or two more things. He takes His time to give this earth its final form.
He might have created the earth and formed it with a word, but He chose the long route to make something special for us, that we may glorify Him.
Having thought about it further, I realise that people might be reducing God to a simple, mundane, familiar concept. We want to make Him like Zeus who is essentially a human being with powers. Worse still, we want to make Him like us - somebody weak and powerless who can essentially do nothing because, in our arrogance, we want to be gods; we want to be all-powerful, to live forever to be ever young and to never die (or at least be guaranteed a better life after death by default). Isn't that the concept behind all superhero movies and vampire movies?