add-acf-field-content-to-product.php

<?php

// Determines what to do - creates the function with your function name
function add_note_to_product() {
	
	// Checks whether the product is in the Hoodies product category
	if ( has_term('hoodies', 'product_cat' ) ) {
	
		// Gets the note field
		$note = get_field( 'note' );

		// Checks whether the field has text in it
		if( $note ) {

			// Outputs the text you entered in the backend
			echo '<p class="my-product-note">' . $note . '</p>';	

		}
		
	}

}

// Determines where to do it - the first part is the hook, the second your function name
add_action( 'woocommerce_after_add_to_cart_button', 'add_note_to_product' );