If the order is in Indian rupee then it is not showing rupee symbol in PDF

Hi,
I am using this plugin, it is working fine.
I am having one issue in it that when the customer pays in Indian currency i.e INR then it is not showing any currency symbol in the PDF generated.

Please provide any solution.

https://www.ads-software.com/plugins/woocommerce-pdf-invoices-packing-slips/