Change Labels and Placeholders

<?php

add_filter( 'woocommerce_checkout_fields' , 'popcorn_labels_placeholders', 9999 );
 
function popcorn_labels_placeholders( $f ) {
 
	// first name can be changed with woocommerce_default_address_fields as well
	$f['billing']['billing_first_name']['label'] = 'Quel est ton nom de famille?';
	$f['order']['order_comments']['placeholder'] = 'Ton surnom?';
 
	return $f;
 
}

//Ou autre code : 

add_filter( 'woocommerce_checkout_fields', 'bbloomer_remove_woo_checkout_fields' );
  
function bbloomer_remove_woo_checkout_fields( $fields ) {
    unset( $fields['billing']['billing_first_name'] ); 
    return $fields;
}