Register custom widget and sidebar

custom_widget.php

<?php

// Register right sidebar


function footer_widget(){
    register_sidebar(array(
        'name'=>'Footer Sidebar',
        'id'=>'footer_widget',
        'description'=>'This is our footer widget',
        'before_widget'=>'<div class="col-md-4"><div class="widget">',
        'after_widget'=>'</div></div>',
        'before_title'=>'<h3 class="widget-title">',
        'after_title'=>'</h3>',
    ));
    
}
add_action('widgets_init', 'footer_widget');

// Register custom widget options

class my_contact_widget extends WP_Widget {

	function __construct() {
		// Instantiate the parent object
		parent::__construct( 
            
            'contact_widget',//id
            'Contact Widget'//name
        
        );
	}
  
    
    function form( $instance ) {
		// Output admin widget options form
        
        
        // stucture: condition ? positive : nagetive  ( here, ? = ternary operator ) 
        
        $title = ! empty ($instance['title']) ? $instance['title'] : esc_html__( 'Type your title', 'text_domain' );
        $icon = ! empty ($instance['icon']) ? $instance['icon'] : esc_html__( 'Address Icon', 'text_domain' );
        $address = ! empty ($instance['address']) ? $instance['address'] : esc_html__( 'Type your company address', 'text_domain' );
        $another_icon = ! empty ($instance['another_icon']) ? $instance['another_icon'] : esc_html__( 'Another Icon', 'text_domain' );
        $mobile = ! empty ($instance['mobile_num']) ? $instance['mobile_num'] : esc_html__( 'Type Contact', 'text_domain' );
        $email_icon = ! empty ($instance['email_icon']) ? $instance['email_icon'] : esc_html__( 'Email Icon', 'text_domain' );
        $email = ! empty ($instance['email']) ? $instance['email'] : esc_html__( 'Email Address', 'text_domain' );

        
        // esc_html__( 'Type your title', 'text_domain' );
        // esc_html__( 'Type your icon name', 'text_domain' );
        ?>

    <p>
        <label>Title</label>
        <input type="text" name="<?php echo esc_attr( $this->get_field_name('title') ); ?>" value="<?php echo $title; ?>">
    </p>
    <p>
        <label>Address Icon</label>
        <input type="text" name="<?php echo esc_attr( $this->get_field_name('icon') ); ?>" value="<?php echo $icon; ?>">
    </p>
    <p>
        <label>Address</label>
        <input type="text" name="<?php echo esc_attr( $this->get_field_name('address') ); ?>" value="<?php echo $address; ?>">
    </p>
    <p>
        <label>Mobile Icon</label>
        <input type="text" name="<?php echo esc_attr( $this->get_field_name('another_icon') ); ?>" value="<?php echo $another_icon; ?>">
    </p>
    <p>
        <label>Mobile Number</label>
        <input type="text" name="<?php echo esc_attr( $this->get_field_name('mobile_num') ); ?>" value="<?php echo $mobile; ?>">
    </p>
    <p>
        <label>Email Icon</label>
        <input type="text" name="<?php echo esc_attr( $this->get_field_name('email_icon') ); ?>" value="<?php echo $email_icon; ?>">
    </p>
    <p>
        <label>Email Address</label>
        <input type="text" name="<?php echo esc_attr( $this->get_field_name('email') ); ?>" value="<?php echo $email; ?>">
    </p>
    <?php
	}
    
    function update( $new_instance, $old_instance ) {
		// Save widget options
        
        
		$instance['title'] = ( ! empty( $new_instance['title'] ) ) ? strip_tags( $new_instance['title'] ) : '';
		$instance['icon'] = ( ! empty( $new_instance['icon'] ) ) ? strip_tags( $new_instance['icon'] ) : '';
		$instance['address'] = ( ! empty( $new_instance['address'] ) ) ? strip_tags( $new_instance['address'] ) : '';
		$instance['another_icon'] = ( ! empty( $new_instance['another_icon'] ) ) ? strip_tags( $new_instance['another_icon'] ) : '';
		$instance['mobile_num'] = ( ! empty( $new_instance['mobile_num'] ) ) ? strip_tags( $new_instance['mobile_num'] ) : '';
		$instance['email_icon'] = ( ! empty( $new_instance['email_icon'] ) ) ? strip_tags( $new_instance['email_icon'] ) : '';
		$instance['email'] = ( ! empty( $new_instance['email'] ) ) ? strip_tags( $new_instance['email'] ) : '';

		return $instance;
        
	}

	function widget( $args, $instance ) {
		// Widget output
        
        echo $args['before_widget'];
        
        if ( ! empty( $instance['title'] ) && ($instance['icon']) && ($instance['address']) && ($instance['another_icon']) && ($instance['email_icon']) && ($instance['email']) ) 
        
        ?>


        <div class="widget">
            <h3 class="widget-title">
                <?php echo $instance['title']; ?>
            </h3>
            <div class="address">
                <p>
                    <span class="icon"><i class="fa fa-<?php echo $instance['icon']; ?>"></i></span>
                    <span class="txt"><?php echo $instance['address']; ?></span>
                </p>
                <p>
                    <span class="icon"><i class="fa fa-<?php echo $instance['another_icon']; ?>"></i></span>
                    <span class="txt"><?php echo $instance['mobile_num']; ?></span>
                </p>
                <p>
                    <span class="icon"><i class="fa fa-<?php echo $instance['email_icon']; ?>"></i></span>
                    <span class="txt"><?php echo $instance['email']; ?></span>
                </p>
            </div>
            <!-- /.address -->
        </div>
        <!-- /.widget -->


        <?php
        
        echo $args['after_widget'];

	}
	
}

function contact_widget() {
	register_widget( 'my_contact_widget' );
}

add_action( 'widgets_init', 'contact_widget' );

gistfile1.txt

Usage Example:
==============

<?php dynamic_sidebar('footer_widget'); ?>