Question

I thought increasing the distance between two or more charges weakens their influence on each other or force
and that decreasing the distance strengthens their influence on each other r force.

In what way Is force between two charges proportional to capacitance?

Answer 1

You're asking quite a few questions bout capacitance that are a little bit off. I suggest going back and understanding from basics what capacitance is and how it works. Your text book is a good thing to look at and you might also enjoy this lecture:
http://ocw.mit.edu/courses/physics/8-02-electricity-and-magnetism-spring-2002/video-lectures/lecture-7-capacitance-and-field-energy/