The header() function sends a raw HTTP header to a client.
Syntax
header(string,replace,resp_code)
Parameters
string − The header string to send.
replace − Indicates whether the header should replace previous or add a second header.
resp_code − It forces the HTTP response code to the specified value
Return
The header() function returns nothing.
Example
The following is an example to save a generated PDF −
<?php
header("Content-type:application/pdf");
header("Content-Disposition:attachment;filename=output.pdf'");
readfile("demo.pdf");
?>The file downloaded will be “output.pdf”, whereas the input is “demo.pdf”.