adding text block via customizer wordpress

Add a New Panel, Section, Setting and Control for the Customizer

<?php
	add_action( 'customize_register', 'genesischild_register_theme_customizer' );
	/*
	* Register Our Customizer Stuff Here
	*/
	function genesischild_register_theme_customizer( $wp_customize ) {
	// Create custom panel.
	$wp_customize->add_panel( 'text_blocks', array(
	'priority' => 500,
	'theme_supports' => '',
	'title' => __( 'Text Blocks', 'genesischild' ),
	'description' => __( 'Set editable text for certain content.', 'genesischild' ),
	) );
	// Add Footer Text
	// Add section.
	$wp_customize->add_section( 'custom_footer_text' , array(
	'title' => __('Change Footer Text','genesischild'),
	'panel' => 'text_blocks',
	'priority' => 10
	) );
	// Add setting
	$wp_customize->add_setting( 'footer_text_block', array(
	'default' => __( 'default text', 'genesischild' ),
	'sanitize_callback' => 'sanitize_text'
	) );
	// Add control
	$wp_customize->add_control( new WP_Customize_Control(
	$wp_customize,
	'custom_footer_text',
	array(
	'label' => __( 'Footer Text', 'genesischild' ),
	'section' => 'custom_footer_text',
	'settings' => 'footer_text_block',
	'type' => 'text'
	)
	)
	);
	// Sanitize text
	function sanitize_text( $text ) {
	return sanitize_text_field( $text );
	}
	} ?> get where to add text block value <?php echo get_theme_mod( 'footer_text_block'); ?> reference: https://wpbeaches.com/adding-text-block-via-customizer-wordpress/