do I have to pass a path in html get request code example

Example 1: how do i set a pdf to be download link in html

<a href="./directory/yourfile.pdf" download="newfilename">Download the pdf</a>

Example 2: How do I get PHP errors to display

//PHP functions
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

//.htaccess
php_flag display_startup_errors on
php_flag display_errors on
php_flag html_errors on
php_flag log_errors on
php_value error_log  /home/path/public_html/domain/PHP_errors.log

Example 3: what Permissions do I need for include folder on php

Directories must have execute permissions to be usable;
Usually this is 0755.
PHP scripts run via mod_php are not executed but rather read;
0644 will suffice for this.