There may have been a time when it could have been considered a reasonable question as to whether the six days of creation in Genesis 1 are literal or figurative. However there is now very strong evidence that the universe is billions of years old, so it cannot be six literal days. There is evidence that the time since the universe was formed (the Big Bang) is 13.7 billion years. Whatever that period is, God has used the time to form a populated earth which will be filled with his glory. So creation has not taken one day, or six days, but billions of years.
Why did God chose to present a six day creation? Part of the reason is that we are expected to see in our own seven day week a parallel of God’s work of creation and his plan of salvation. The seventh day of rest prefigures the climax of his creation when his kingdom will be established.
Heb 4:4-11 For he has somewhere spoken of the seventh day in this way: “And God rested on the seventh day from all his works.” (5) And again in this passage he said, “They shall not enter my rest.” (6) Since therefore it remains for some to enter it, and those who formerly received the good news failed to enter because of disobedience, (7) again he appoints a certain day, “Today,” saying through David so long afterward, in the words already quoted, “Today, if you hear his voice, do not harden your hearts.” (8) For if Joshua had given them rest, God would not have spoken of another day later on. (9) So then, there remains a Sabbath rest for the people of God, (10) for whoever has entered God’s rest has also rested from his works as God did from his. (11) Let us therefore strive to enter that rest, so that no one may fall by the same sort of disobedience.