Thanks Florent .
Apologies for the delayed response .
1. We are planning to use this for one time only and remaining will be given back to client as unused marked .
2. We will definitely filter recipients on some filters like people purchasing some items will get this voucher .
3. Voucher code will be provided by client so that it can be used while booking on the website . This is something will be given to us in a flat file .
Please find above some of the answers to your question .
Basically we have a workflow running that send email to some set of people after proper segmentation . Now , client wants to include one user one voucher code from a flat file (To be provided by client) .
Regards,
Vipin