Wordpress Customizer Setup

add_action( 'customize_register', 'registerSection' );

function registerSection( $wp_customize ){

  $section_key = "custom_section_key";

  $wp_customize->add_section( $section_key, array(
    'title'    => "Section Title",
    'priority' => 160,
  ) );

  $setting_id = "custom_setting_id";

  $wp_customize->add_setting( $setting_id, array(
    'default'    => '',
    'transport'  => 'refresh',
    'capability' => 'manage_options',
    'type'       => 'option',
    'sanitize_callback' => 'sanitize_text_field'
  ) );

  $wp_customize->add_control( $setting_id, array(
    'label'    => 'Option Label',
    'section'  => $section_key,
    'settings' => $setting_id,
    'type'     => 'text',
    'active_callback' => function () { return true; },
  ) );
};