You can easily set watermark to invoice. You can directly set watermark text or watermark image. These all are settings and can be set directly in defaultSettings file. MPFD has also many function related to watermark that can be also used directly on mpdf object.
$xinvoice = new Xinvoice(); $xinvoice->setSettings("watermark", true);//this will display watermark text set in config //You can also set watermark text and watermark image in settings in same way or it can be set directly in config. //$xinvoice->setSettings("watermarkType", "text");//whether text or image watermark //$xinvoice->setSettings("watermarkValue", "Your Company Name");//Watermark text or image value echo $xinvoice->render();