Electro - Single product custom download button

functions.php

/**
 * 1. Add custom Download Link and Button Text fields on single product edit page.
 */
add_action( 'woocommerce_product_options_general_product_data', 'ec_child_add_download_button_fields' );

function ec_child_add_download_button_fields() {
	echo '<div class="options_group">';

	woocommerce_wp_text_input(
		array(
			'id'          => '_custom_download_button_text',
			'label'       => __( 'Download Button Text', 'electro-child' ),
			'placeholder' => __( 'Download', 'electro-child' ),
			'desc_tip'    => false,
			'description' => __( 'Enter custom label for the download button.', 'electro-child' ),
		)
	);

	woocommerce_wp_text_input(
		array(
			'id'          => '_custom_download_button_url',
			'label'       => __( 'Download Button URL', 'electro-child' ),
			'placeholder' => 'https://...',
			'desc_tip'    => false,
			'description' => __( 'Enter the custom link/URL for the download button.', 'electro-child' ),
			'type'        => 'url',
		)
	);

	echo '</div>';
}

/**
 * Save custom fields when product is updated/saved.
 *
 * @param int $post_id Product post ID.
 */
add_action( 'woocommerce_process_product_meta', 'ec_child_save_download_button_fields' );

function ec_child_save_download_button_fields( $post_id ) {
	if ( isset( $_POST['_custom_download_button_text'] ) ) {
		update_post_meta( $post_id, '_custom_download_button_text', sanitize_text_field( wp_unslash( $_POST['_custom_download_button_text'] ) ) );
	}

	if ( isset( $_POST['_custom_download_button_url'] ) ) {
		update_post_meta( $post_id, '_custom_download_button_url', esc_url_raw( wp_unslash( $_POST['_custom_download_button_url'] ) ) );
	}
}

/**
 * 2. Load button on single product frontend.
 */
add_action( 'init', 'ec_child_single_product_custom_button', 10 );

function ec_child_single_product_custom_button() {
	add_action( 'woocommerce_single_product_summary', 'single_product_custom_button_after_add_to_cart', 31 );
}

function single_product_custom_button_after_add_to_cart() {
	global $product;

	if ( ! is_a( $product, 'WC_Product' ) ) {
		$product = wc_get_product( get_the_ID() );
	}

	if ( ! $product ) {
		return;
	}

	$button_url  = get_post_meta( $product->get_id(), '_custom_download_button_url', true );
	$button_text = get_post_meta( $product->get_id(), '_custom_download_button_text', true );

	// Only display if a download link is provided.
	if ( empty( $button_url ) ) {
		return;
	}

	if ( empty( $button_text ) ) {
		$button_text = __( 'Download', 'electro-child' );
	}
	?>
	<div class="custom-button custom-download-button">
		<a href="<?php echo esc_url( $button_url ); ?>" class="button" target="_blank" rel="noopener noreferrer">
			<?php echo esc_html( $button_text ); ?>
		</a>
	</div>
	<?php
}