add shortcode in wordpress

1function create_shortcode(){
2    return "<h2>Hello world !</h2>";
3}
4add_shortcode('my_shortcode', 'create_shortcode');
5// Use [my_shortcode]

1<?php echo do_shortcode('[name_of_shortcode parameters=""]'); ?>

1function wpdocs_bartag_func( $atts ) {
2    $atts = shortcode_atts(
3        array(
4            'foo' => 'no foo',
5            'bar' => 'default bar',
6        ), $atts, 'bartag' );
7 
8    return 'bartag: ' . esc_html( $atts['foo'] ) . ' ' . esc_html( $atts['bar'] );
9}
10add_shortcode( 'bartag', 'wpdocs_bartag_func' );

1// function that runs when shortcode is called
2function wpb_demo_shortcode() { 
3 
4// Things that you want to do. 
5$message = 'Hello world!'; 
6 
7// Output needs to be return
8return $message;
9} 
10// register shortcode
11add_shortcode('greeting', 'wpb_demo_shortcode'); 

1function wp_demo_shortcode() { 
2
3//Turn on output buffering
4ob_start();
5$code = 'Hello World';
6ob_get_clean();
7
8 // Output needs to be return
9return $code;
10} 
11
12// register shortcode
13add_shortcode('helloworld', 'wp_demo_shortcode'); 

1// function that runs when shortcode is called
2function wpb_demo_shortcode() { 
3 
4// Things that you want to do. 
5$message = 'Hello world!'; 
6 
7// Output needs to be return
8return $message;
9} 
10// register shortcode
11add_shortcode('greeting', 'wpb_demo_shortcode'); 
12