It’s a way to describe that one thing can cause another thing to happen and that from our perspective this doesn’t happen instantaneously.
Time exists in the same way that numbers do. It’s just a definition that allows us to tell things apart. Time and numbers don’t exist by themselves, but the definition will always be necessary to describe things that do exist.
Even the most simple description implies time and quantity. F.i. the sentence “apple is red” doesn’t mention the time or quantity directly, but the word “is” implies both time (present) and quantity (singular) and existence.
Saying only “red apple” doesn’t imply existence, so we can’t say that it describes anything that exists.
So the purpose of the human invention of the time concept is to describe existence. The meaning is dependant on what definition you use.
My simplistic answer, time exists so we can quantify change. In a static universe without time, could there be any change? Without change, there is no life.
Imagine all moments of your life existing as a continuum- like a movie. When you don’t watch the movie, it still exists and there are still changes - the beginning is different from the end. But the changes are spatial, not temporal. It’s more like a painting that you can admire as a whole. Does that mean there’s no life? I really don’t know.