I was told that DirectX is basically a software that enhances computer. Is it right? Is it really important to have it to run this game?
What you're trying to say is, Intel/Nvidia, as long as my memory's good and RAM's tip-top then I can play PZ without any hassle?
Forgive my computer incompetence.
You are forgiven.
DirectX is not basically software. It is a collection of "application programming interfaces" more commonly known as API's, which can be seen as software between the game / program on the computer and the hardware of the computer. It's like a "middle man". It lets the games / programs on the computer use the hardware of the computer. Certain games, such as Planet Coaster for example, are designed to use specific graphics elements which are only available for DirectX 11 and higher. In order to run a game that requires DirectX 11, you will not only need to have DirectX 11 software installed on your computer, which is the "middle man" between game and hardware, but you will also need a graphics card that is capable of supporting DirectX 11 features. Without a graphics card that supports DirectX 11 or higher you cannot run the game (it won't start).
To answer your questions;
Yes, it is important to have a graphics card that supports the required version of DirectX. Without it you cannot play the game.
What I am trying to say is, check the minimum requirements of Planet Zoo. If your computer meets or exceeds those, then you will be fine and you can play Planet Zoo.
You can find the minimum requirements for Planet Zoo here:
Planet Zoo pre-order FAQ.
Good luck!