To explain my question in a better way I will first talk about gravitation!

**According to wikipedia:** 

Gravity is most accurately described by the general theory of relativity (proposed by Albert Einstein in 1915) which describes gravity not as a force, but as a consequence of the curvature of spacetime caused by the uneven distribution of mass.

**What I think about that statement in wikipedia:**

Gravity is not a force and the effects of gravity are ascribed to spacetime curvature

**My comments:**

Newton said that two objects kept far way would attract each other by some animal force called gravity.But,he didn't explain how the force could be present between the two objects placed a long distance apart,it was Einstein who did it.He called gravity not a force,but a consequence of curvature of spacetime caused by the unequal distribution of mass.

**Result:** Gravity explained! i.e If I ask newton what causes gravity and how can two objects placed far apart attract each other, he wouldn't be able to answer properly.But, Einstein can and he would give a lecture on General theory of relativity.

**NOTE:**

The major drawback of newton's theory of gravity is that it considers gravity to be a instantaneous force.Relativity puts a *limit to the speed with which information can travel.*

I think that electrostatic force can't be instantaneous, because there is a limit to the speed with which information can travel.


**My question:** 

How do you explain electrostatic force?

Let's talk about  electrostatic force between two opposite charges and gravitational force between two other objects.The electrostatic force follows the inverse square law similar to newtons law of gravity.But,we know that Newton's concept of force doesn't accurately describe gravity.Gravity is a consequence of curvature of spacetime.So,if I ask a question: what is the cause of gravitational force and why it isn't instantaneous, you could explain me General relativity.

But,what if I asked you: what is the cause of electrostatic force and why it isn't instantaneous ?...

**To put it simply:**

What is the,fundamental, cause of Electrostatic force and How do you explain the fact that it isn't instantaneous?

**Note:**

You could say that electrostatic force is attraction or repulsion between charges,but I could still ask :why should there be any attraction or repulsion?  

**Request:**

Those who downvoted my answer:please provide an explanation for doing so ,so that I will either edit or delete my question!

**References:**

https://www.youtube.com/watch?v=o1abyP4zfGg (time=3:22)