Get value from an input field and pass into update_meta_data as $meta_value

I am building a woocommerce site and I have some input fields the on the product page. one is for recipient email (its for a gift car). Everything works, and the recipient email is saved on the order, but I want to be able to pass the email address to a function to update_meta_data so that I can use in other parts of the code (namely to send out a separate email to the recipient to redeem the card).

here is the function I am trying to use:

add_action('woocommerce_checkout_update_order_meta',function( $order_id, $posted ) {

    $order = wc_get_order( $order_id );
    $order-update_meta_data( 'recipient_email', "[email protected]" );
    $order-save();
} , 10, 2);

Where "joe@acme" is, I want to pass the value from the form. the form is rendered using a custom form plugin. the html of the form looks like this:

input name="recipient_email" id="recipient_email" data-type="text" data-req="on" data-message="no email" maxlength="255" style="width: 100%; padding: 0px;" type="text"

As I said, the form works to save the recipient email to the order, but not as post meta data, so I don't know how to retrieve and store as a variable that I can use for for other parts of the code.