Where are double pointer used and how they work in C and why pointer concepts are not there in interpreted language?

Answer 1

If you know how pointers with single pointer works, then its pretty much the same with double pointers. It just pointer to a pointer.
More detailed visualized explanation:
https://www.tutorialspoint.com/cprogramming/c_pointer_to_pointer.htm

Every languages have pointers because every languages need to interact with the memory.
But the only difference is that in pointer-free languages there is "automatic memory management"(garbage collector) so we don't have to worry much on how to handle and implement pointers.
While on the other hand, languages with pointers give us the chance to play and handled memory of our own. So in such a language, usually the programmer is the garbage collector themselves.

This is just a brief idea and what I think.

Answer 2

In Languages like PYTHON, java and C# you doesn't need to interact with memory because of garbage collector.

That is why you doesn't need pointers in those languages.

Double pointer points to another pointer.