How to make own c++ header file, and what it can be included

Question

C++ header file

Answer 1

Header files contain definitions of Functions and Variables, which is imported or used into any C++program.

Answer 2

create new file with extension of .h
e.g: example.h
add this file to the. cpp file.
#include "example.h"
that's all.

Answer 3

In header file, what we can do more

Answer 4

Any example ?