While the characteristics are debated, there are six commonly recognized ones that make up a civilization. These traits include Social/Economic Classes, Art and Architecture, Written Language, Area, Government, and Religion.
To go deeper into each of these characteristics:
-Area: The area of a civilization is where it resides. Things like a capital city, states or city-states, and the borders of the civilization would all fall into this category.
-Written Language: As it states in the title, having a language to speak and write in is important for communication, collaboration, and historical documentation.
-Art and Architecture: Art and Architecture are the two most common creative pieces that make a civilization unique. Architecture can create monuments, bridges, or even just houses that make the civilization stick out, while art can range from creative expression to useful products such as pottery.
-Government: A government, to some degree, is required to ensure that the civilization has rules and those rules are enforced. In a civilization, there needs to be a leader or group of leaders to confirm that the laws will be followed.
-Religion: Whether a religion is in place or none at all, it's important for a civilization to have a standard set of beliefs. Religion can create certain buildings such as churches, can inspire philosophers and scientists, and can ensure greater quality of life.
-Social/Economic Classes: There must be some sort of hierarchy in place no matter the style of government. Whether it's based on wages, power, or occupation, there must be some form of greater than/ lesser than in place when it comes to power.
Hope this helped! :)