How to enable order comments/notes field on Handsome Checkout pages without 3rd party plugins?

You need to add this code snippet into functions.php file of your theme.

function bf_keep_order_comments_field( $fields )
{
    if( empty( $fields['order'] ) )
    {
        $fields['order'] = array();
    }

    if( empty( $fields['order']['order_comments'] ) )
    {
        $fields['order']['order_comments'] = array(
            'type'        => 'textarea',
            'class'       => array( 'notes' ),
            'label'       => __( 'Order notes', 'woocommerce' ),
            'placeholder' => esc_attr__(
                'Notes about your order, e.g. special notes for delivery.',
                'woocommerce'
            ),
        );
    }

    return $fields;
}
add_filter( 'woocommerce_checkout_fields', 'bf_keep_order_comments_field', 100 );

function bf_keep_order_comments_field( $fields )

{

if( empty( $fields['order'] ) )

{

$fields['order'] = array();

}

if( empty( $fields['order']['order_comments'] ) )

{

$fields['order']['order_comments'] = array(

'type' => 'textarea',

'class' => array( 'notes' ),

'label' => __( 'Order notes', 'woocommerce' ),

'placeholder' => esc_attr__(

'Notes about your order, e.g. special notes for delivery.',

'woocommerce'

);

}

return $fields;

}

add_filter( 'woocommerce_checkout_fields', 'bf_keep_order_comments_field', 100 );