Add Custom Field to Single Product Page WooCommerce

In WooCommerce, If you want to add custom field in single product page than here is solutions. In this example i was add recommended retail price(RRP). It’s price which manufacturer recommends retailer to sell the product. It will display in any Ads or magazine. Like “RRP : ₹500 ” and main price : ₹ 200

So here is code. Add below line of code in your theme’s functions.php file of your active child theme (or theme) and save the file.

// 1) Add RRP field to product pricing tab (admin)
add_action( 'woocommerce_product_options_pricing', 'wc_add_rrp_field' );
function wc_add_rrp_field() {
    woocommerce_wp_text_input( array(
        'id'          => '_rrp',
        'label'       => __( 'RRP', 'woocommerce' ) . ' (' . get_woocommerce_currency_symbol() . ')',
        'class'       => 'short wc_input_price',
        'type'        => 'text',
        'description' => __( 'Recommended Retail Price (optional).', 'woocommerce' ),
        'desc_tip'    => true,
    ) );
}

// 2) Save RRP when product is saved (WooCommerce admin handler)
add_action( 'woocommerce_process_product_meta', 'wc_save_rrp_field', 10, 1 );
function wc_save_rrp_field( $post_id ) {
    if ( isset( $_POST['_rrp'] ) ) {
        // sanitize and format decimal for storage
        $rrp_raw = wp_unslash( $_POST['_rrp'] );
        // remove currency symbols/commas etc and convert to decimal
        $rrp_clean = wc_format_decimal( $rrp_raw );
        if ( $rrp_clean !== '' && is_numeric( $rrp_clean ) ) {
            update_post_meta( $post_id, '_rrp', $rrp_clean );
        } else {
            // delete if empty or invalid
            delete_post_meta( $post_id, '_rrp' );
        }
    } else {
        delete_post_meta( $post_id, '_rrp' );
    }
}

// 3) Display RRP on single product page (before price)
add_action( 'woocommerce_single_product_summary', 'wc_display_rrp_on_product', 9 );
function wc_display_rrp_on_product() {
    global $product;

    if ( ! is_a( $product, 'WC_Product' ) ) {
        return;
    }

    // skip variable products (if that's intended)
    if ( $product->is_type( 'variable' ) ) {
        return;
    }

    $rrp = get_post_meta( $product->get_id(), '_rrp', true );

    if ( $rrp !== '' && is_numeric( $rrp ) ) {
        // format and escape output
        $formatted = wc_price( $rrp );
        echo '
' . esc_html__( 'RRP:', 'woocommerce' ) . ' ' . wp_kses_post( $formatted ) . '
';
    }
}