Simply put, worldview is how someone views the world. A person's worldview sets the standards in which they compare everything to. Deciding what is right, and what is wrong, is just one example of why a person's worldview matters. Someone's worldview helps them answer the questions: Who are you? What are you living for? Who do you want to be?
Everyone has a religious worldview, meaning that everyone has an opinion on God's existence. All worldviews address God, from both ends of the "is He real" spectrum, and in- between. After deciding on how one feels about God, they model their lives accordingly. Then, because they are human and it is in their nature, they attempt to convert others to thinking and living the way they do.
There are many different variations of worldview. While there are some that are more widely known than others, there are many to choose from. Atheists believe without a doubt that there is no God. Agnostics do not believe that there is enough information to determine whether God is real or not. Unitarians believe in God, but do not believe that Jesus was the human embodiment of him. Christians, the opposite of Atheist, believe wholeheartedly that there is a god, and that He is a great, and almighty god.
The Christian worldview is that all truth belongs to and comes from God. God is the one who sets the standards, in which Christians structure their lives around. God lays out how to be a "good" person in the Bible. Christians believe that there is a Divine Law, and that is how they can explain morals, ethics, value, and much more. He teaches that He put everyone on Earth for a purpose. Christians spend their lives trying to figure out what that purpose is, and then fulfilling it to the best of their ability. The Christians see that there is purpose in everything because God has created everything for some reason. He never does something "just because" like people often do. One of the basic Christians thoughts about worldview is that there is meaning and purpose before you were born, there is meaning and purpose to your life, and there will be meaning and purpose after your death.
One can only "unlock" their purpose when they accept that God has given them one. Also, that they should not look to society to judge if they are successful. Society will judge a hammer on how well it can paint a car, and then tell the hammer it is useless and is only capable of bringing destruction. The hammer will only find its true purpose when it seeks the guidance of God (He will graciously direct Mr. Hammer to the nails). Then the hammer will be useful, and be filled with the joy of contentment.
Humans have the choice to believe however they choose. No matter how one chooses to belive, it is important to be aware of your worldview, as well as others.