Update an order custom field after order complete in Craft 3 I am trying to update an order's custom field after order complete. 
I set it like this in my plugin:

Event::on(Order::class, Order::EVENT_AFTER_COMPLETE_ORDER, function(Event $e) {
        $order = $e-&gt;sender;
        $order-&gt;setFieldValue("customFieldHandle", "My value");
    });


But it is not working. I guess I used the wrong method to do it.
What I wrote is correct. I debugged it, and I had a problem in another place where the order did not get completed in the first place. silly me LOL.
So my answer is:

Event::on(Order::class, Order::EVENT_AFTER_COMPLETE_ORDER, function(Event $e) {
    $order = $e-&gt;sender;
    $order-&gt;setFieldValue("customFieldHandle", "My value");
});