File Storing Different Datatypes

Question

Can a file store any type of input or a specific type? Do we have to define it?
Like if I have to write an integer with a string. Is it possible to write like that?

Answer 1

any type can be write by php
file_get_content();
file_put_content($data);

if you want right something like picture you must use image module of php
but any string or integer can write to file by second function as data variable