Drawing with 3D Cartesian Coordinates
The threedimensional (3D) Cartesian coordinate system (also called 3D rectangular coordinates) is the natural extension of the 2D Cartesian graph. The key difference is the addition of a third axis, the zaxis, extending perpendicularly through the origin.
Drawing a 3D graph in two dimensions is kind of tricky. To get a better sense about how to think in 3D, hold up the figure where you can compare it with the interior corner of a room (not a round room!). Note the following:

The xaxis corresponds to where the lefthand wall meets the floor.

The yaxis corresponds to where the righthand wall meets the floor.

The zaxis corresponds to where the two walls meet.
Just as the 2D Cartesian graph is divided into four quadrants, the 3D graph is divided into eight octants. From your perspective as you look at the graph, you’re standing inside the first octant, where all values of x, y, and z are positive.
The figure above shows the complete 3D Cartesian system with the point (1, 2, 5) plotted. In similarity with regular Cartesian coordinates, you plot this point by counting 1 unit in the positive x direction, and then 2 units in the positive y direction, and finally 5 units in the positive z direction.