Snap to Points
Snap to Points mode allows you to digitise a point that is 'snapped' to an existing point. The main difference between between
Snap to Points mode and
Snap to Objects mode is that the latter allows snapping to any graphical entity whereas
Snap to Points mode only allows snapping to points or apparent intersections.
The maximum distance the cursor can be from the object and still snap to the object is defined by the pick aperture, which is set through the Graphics : Input section of the Tools > Preferences option.
You can use the keyboard shortcut to switch to Snap to Points by pressing the I key when in point insertion mode,
1- Point and Object Snap modes