Usually graph paper is marked off with lines that are spaced equally along the x and y axes. In this case the x and y axes are scaled identically. One unit of physical distance along the x-axis is equal in length to one unit of physical distance along the y-axis. This arrangement forms a grid of squares.
However, it is important to understand that the two axes can be scaled differently. For example, 1 centimeter might separate the coordinates x = 0 and x = 1 along the x-axis, while 2 centimeters might separate the the coordinates y = 0 and y = 1 along the y-axis. This arrangement forms of grid of rectangles that are twice as tall as they are wide. One could think of the graph paper stretching in the y direction.
In the following demonstration you can change the scaling of the graph paper both in the x and the y directions. Notice how this changes the shapes of the functions that are drawn on the graph paper.