What is pointer?

Answer 1

A pointer is a variable that stores a memory address.

Answer 2

Pointers are the variables that stores the address of the another variables

Answer 3

pointers are basically containers of an address of a variable, imagine you have a variable that consists some data in it and you want to store it somewhere or even do something with it using another variable, you can make so many uses out of it.
now why we use them?
soetimes we want to work with registers or some parts of our memory so we have to use a pointer to read or write data from it.

Answer 4

This explains what they are and how they work:
https://youtu.be/JAwQrsW1o3k