Gift Voucher supports creating your vouchers as PDFs to be downloaded by the user and sent to their recipient. This allows you to create visually attractive designs for your vouchers, as opposed to a simple number in an email (which you can of course also do!).
Behind the scenes, we use Dompdf, the same PDF library that Craft Commerce uses.
The above shows an example of a PDF voucher you can generate. Of course, the design is 100% up to you, but you might like to get started with our PDF Template →.
Available for Craft 2 for $99, trial locally for as long as you need.