How add automatically a fee when a customer send a quote

If you want add a fee when a customer send a quote, add this custom code in your functions.php

if ( !function_exists( 'ywraq_add_quote_fee' ) ) {
    add_action( 'ywraq_after_create_order', 'ywraq_add_quote_fee', 20, 1 );

    function ywraq_add_quote_fee( $order_id ) {

        $order = wc_get_order( $order_id );

        $order_total = $order->get_total();
        $fee         = $order_total * 5 / 100; //for example the fee is the 5% of the total
        $item        = new WC_Order_Item_Fee();
        $item->set_props( array(
            'name'      => 'Quote Fee',
            'tax_class' => 0,
            'total'     => $fee,
            'order_id'  => $order_id,
        ) );
        $item->save();
        $order->add_item( $item );
        $order->calculate_totals();
    }
}

This code add a fee of 5% on the order total