widget-skeleton.php

<?php

class Widget_Name extends WP_Widget {
  function Widget_Name() {

     $widget_opts = array(
      'classname' => 'your-awesome-class',
      'description' => 'Your awesome Description',
    );
    
    $this->WP_Widget('your_awesome_cool_name', 'Awesome Title', $widget_opts);  
  }

  // widget outputs the widget content. 
  function widget($args, $instance) {
  }

  // displays the form which shows on the Widgets management panel. 
  function form($instance) {
    $output = '';
    $instance = (array) $instance;

    $instance = wp_parse_args($instance, array('number' => 2 ));

    $title = esc_attr($instance['title']);

    // More Code

    echo $output;
  }

  // updates the widget options when saved. 
  function update($new_instance, $old_instance) {
    $instance = $old_instance;
    $instance['title'] = strip_tags($new_instance['title']);
    return $instance; 
  }
}

// Load and Register the widget
add_action('widgets_init', 'awesome_plugin_name_load_widgets');

function awesome_plugin_name_load_widgets() {
  register_widget('Widget_Name');
}