The command is available via the icon 
in the status bar and the hotkey F7. It switches on/off the display of a rectangular grid of points situated at a certain distance from each other. The grid is used for a more effective drawing of elements. The grid step can be set by the user. While creating and editing the objects snap to the mesh points is active. Grid isn't printed.
The grid step is specified in the tab Snap and Grid of the window Options. By default the grid step is calculated automatically from the size of the drawing and is equal to one hundredth of its largest side. The size of the image are displayed in the right bottom corner of the program in the format X;Y;Z. The user can manually set the grid step along the axes X and Y in the window Options.
To get a quick access to the needed tab of the dialog box Options right click on the grid icon in the status bar and select Grid and Snap Options. The dialog box Options with the opened tab Snap and Grid will appear.