How to create plugin in wordpress?

To create plugin in wordpress follow below steps

Step1:
Create folder with your plugin name. Create php file with your plugin name. Now put blank index.php file for folder security.

Step2:
Write down plugin name in your plugin file as below.
/*
Plugin Name: Your plugin name
Description: Your demo plugin
Author: Shailesh
*/
Step3
Check your admin side and see plugin is listed on plugin page.

You need to avtivate the plugin.

How can i replace (wordpress) in email header?

To remove wordpress from email Header add below filter.
add_filter(‘wp_filter_email’, custom_wp_filter_email’);
add_filter(‘wp_filter_email_from’, ‘custom_wp_filter_email_from’);

function custom_wp_filter_email() {
$email = get_option(‘admin_mail’);
if(!$email) {
$email = admin@domain.com;
}
return $email;
}

function custom_wp_filter_email() {
$from = get_bloginfo);
if(!$from) {
$from = ‘Your name’;
}
return $from;
}