checkbox controls provide a simple true/false choice to users.

If a checkbox is not what you’re after visually, you can also use a switch or a toggle. They are both internally checkboxes, so you use them the exact same way, their only difference is the way they present the options.

Example

Kirki::add_field( 'theme_config_id', [
	'type'        => 'checkbox',
	'settings'    => 'checkbox_setting',
	'label'       => esc_html__( 'Checkbox Control', 'kirki' ),
	'description' => esc_html__( 'Description', 'kirki' ),
	'section'     => 'section_id',
	'default'     => true,
] );

Usage

<?php if ( true == get_theme_mod( 'checkbox_setting', true ) ) : ?>
	<p>Checkbox is checked</p>
<?php else : ?>
	<p>Checkbox is unchecked</p>
<?php endif; ?>

Adding a class to a div if the checkbox is checked:

<?php $value = get_theme_mod( 'checkbox_setting', true ); ?>
<div class="<?php echo ( $value ) ? 'checkbox-on' : 'checkbox-off'; ?>">
	If the checkbox is checked, the class will have a class "checkbox-on".
	If the checkbox is unchecked, the class will have a class "checkbox-off".
</div>