In order to replace the barcode number with scannable barcode of type “EAN” use <barcode> tag in the pdf template.
But using the code results an error
<barcode style="width: 264px; height: 45px; margin:8px;margin-left:-7px;" codetype="ean13" showtext="true" value="${barcodeVariable?html}"/>
In order to bring the EAN type of barcode in the invoice form use code:
<barcode bar-width="2" codetype="ean13" showtext="true" height="60" value="${barcodeVariable?html}"/>