Electric lines of force are just imaginary lines, which indicate the direction of force. These lines help us in understanding nature of charges and the force in which charges attract or repel each other.

Usually we draw lines originating from positive charge and terminating at the negative charge. These lines are continuous and cannot be terminated without having the negative charge and continuously go to the infinity.

Example:

As we see from the above figures that positive charge originates the lines, while negative charge terminates. Also there is another thing we should have to remember is that as we go away from the charged body gap between lines increases and hence density or intensity decreases, and causes weaker field intensity as that point. So from these lines we can say that intensity is maximum at the minimum distance between charged body, and if we have to get maximum intensity we’ll have to come closer to it.