Register sidebar

register-sidbar.php

<?php

/**
 * Register widget area.
 *
 * @link https://developer.wordpress.org/themes/functionality/sidebars/#registering-a-sidebar
 */
 
function stock_humayunbd_widgets_init() {
	register_sidebar( array(
		'name'          => esc_html__( 'Footer Widget', 'stock-humayunbd' ),
		'id'            => 'stock_footer',
		'description'   => esc_html__( 'Add Footer widgets here.', 'stock-humayunbd' ),
		'before_widget' => '<div class="col-md-3 col-sm-6"><div id="%1$s" class="widget %2$s">',
		'after_widget'  => '</div></div>',
		'before_title'  => '<h4 class="widget-title">',
		'after_title'   => '</h4>',
	) );
}
add_action( 'widgets_init', 'stock_humayunbd_widgets_init' );

widget-callbacks.php

<?php

// widget callbacks.

if(is_active_sidebar('stock_footer')) : ?>
<div class="row">
	<?php dynamic_sidebar('stock_footer'); ?>
</div>

<?php endif; ?>