WooCommerce - Adds a custom message about how long will take to delivery.

functions.php

<?php
/**
 * Adds a custom message about how long will take to delivery.
 */
function my_wc_custom_cart_shipping_notice() {
	echo '<tr class="shipping-notice"><td colspan="2"><small>';
	_e( '<strong>Atenção:</strong> O prazo de entrega começa a contar a partir da aprovação do pagamento.', 'my-text-domain' );
	echo '</small></td></tr>';
}

add_action( 'woocommerce_cart_totals_after_shipping', 'my_wc_custom_cart_shipping_notice' );
add_action( 'woocommerce_review_order_after_shipping', 'my_wc_custom_cart_shipping_notice' );

/**
 * Adds a custom message about how long will take to delivery in emails.
 *
 * @param  WC_Order $order         Order data.
 * @param  bool     $sent_to_admin True if is an admin email.
 */
function my_wc_custom_email_shipping_notice( $order, $sent_to_admin ) {
	if ( $sent_to_admin ) {
		return;
	}

	_e( '<strong>Atenção:</strong> O prazo de entrega começa a contar a partir da aprovação do pagamento.', 'my-text-domain' );
}

add_action( 'woocommerce_email_after_order_table', 'my_wc_custom_email_shipping_notice', 100, 2 );