The grid can help you place objects on a sheet. It can also be useful when you resize an object or sheet with the mouse.
To show or hide the grid, use the View > Grid (Cmd-') command in the main menu. It is possible to show or hide the grid using the drop-down menu in the Control panel.
To make an object or its part snap to the grid, activate the Snap to Grid feature using the drop-down menu shown above, or use View > Snap to Grid (Cmd-Shift-').
The program Preferences has an option to change the color of the grid.