Capture UTMs/Gclid in registration form

You can add any UTM fields and handl_ fields Native WP Shortcodes to your registration form.

function handl_woocommerce_add_fileds_to_register() {?>
    <p class="form-row form-row-wide">
        <label for="reg_gclid"><?php _e( 'Gclid', 'woocommerce' ); ?></label>
        <input type="hidden" class="input-text" name="gclid" id="reg_gclid" value="<?php esc_attr_e( $_COOKIE['gclid'] ); ?>" />
    </p>
    <div class="clear"></div>
	<?php
}
add_action( 'woocommerce_register_form_start', 'handl_woocommerce_add_fileds_to_register' );