We exist because God decided to make us and the rest of the Universe exist. Some people believe they evolved from apes or some accidental collision of dusts. If that is you, then your context is different. An accident of existence can only accidentally make any meaning. And I wonder how an unintelligent and unintentional existence can make any sense. If you are just some product of chemical of no source, then there is no real need for a meaning to your life. You are just happening.

But we believe that humans were created by God. He is a wise and intentional God, so our lives are meaningful.