Elementor Custom Control

controls.php

<?php

namespace ElementorControls;

if ( ! defined( 'ABSPATH' ) ) exit; // Exit if accessed directly

class Elementor_Custom_Controls {

    private static $_instance = null;

	public static function instance() {
		if ( is_null( self::$_instance) ) {
			self::$_instance = new self();
		}
		return self::$_instance;
    }
    
	public function includes() {
		require_once( __DIR__ . '/custom.php' );
	}

	public function register_controls() {

		$this->includes();
		
		$controls_manager = \Elementor\Plugin::$instance->controls_manager;
		$controls_manager->register_control( 'CUSTOM', new Controls\Elementor_Custom() );

	}

	public function __construct() {
		  add_action( 'elementor/controls/controls_registered', [ $this, 'register_controls' ] );
  }
    
}

Elementor_Custom_Controls::register_controls();

custom.php

<?php

namespace ElementorControls\Controls;

if ( ! defined( 'ABSPATH' ) ) exit; // Exit if accessed directly

class Elementor_Custom extends \Elementor\Base_Control {

	public function get_type() {
        return 'custom';
    }

	public function content_template() {
        echo '<input type="text" placeholder="custom" data-setting="post" />';
    }

}

widget.php

<?php

namespace ElementorWidgets\Widgets;

use Elementor\Widget_Base;
use Elementor\Controls_Manager;

if ( ! defined( 'ABSPATH' ) ) exit; // Exit if accessed directly

/**
 * Elementor Custom Widget
 *
 * Elementor widget.
 *
 * @since 1.0.0
 */
class Custom_Widget extends Widget_Base {

 /* ...  */
 
 	/**
	 * Register the widget controls.
	 *
	 * Adds different input fields to allow the user to change and customize the widget settings.
	 *
	 * @since 1.0.0
	 *
	 * @access protected
	 */
 	protected function _register_controls() {
		$this->start_controls_section(
			'section_content',
			[
				'label' => __( 'Content', 'elementor-case-teaser' ),
			]
		);

		$this->add_control(
			'title',
			[
				'label' => __( 'Custom', 'elementor-custom-control' ),
				'type' => Controls_Manager::CUSTOM,
			]
		);

        $this->end_controls_section();
        
 /* ...  */
 
}