@shahid84: You can add the additional option to the customizer via child theme as below. Add the following codes in your child theme’s functions.php file.
function clean_business_child_customize_register( $wp_customize )
{   
    $wp_customize->add_section( 'my_section', array(
        'description'   => esc_html__( 'This Is My Custom Section', 'clean-business-pro' ),
        'priority'      => 105,
        'title'         => esc_html__( 'My Section', 'clean-business-pro' ),
    ) );
    $wp_customize->add_setting( 'some_field', array(
        'capability'        => 'edit_theme_options',
        'sanitize_callback' => 'sanitize_text_field'
    ) );
    $wp_customize->add_control( 'some_field', array(
        'label'  => esc_html__( 'Some Text Field', 'clean-business-pro' ),
        'section' => 'my_section',
        'settings' => 'some_field',
        'type'   => 'text',
    ) );
}
add_action( 'customize_register', 'clean_business_child_customize_register' );
If you are not familiar with this or coding, I recommend you to hire a customizer.
Regards,
Mahesh