WP Gift Certificate Lite is a plugin which allows you to manage and sell printable gift certificates on your website using QR encoding image.
To place the certificate in any page or post, use [giftcertificateslite].
WPGC (WP Gift Certificate Reloaded) flow will require IPN to be set in PayPal website. It needs to be turned on (through PayPal) and place the url of your domain name, you can use http://www.place-your-domain-name-here.com/, note that you need to include the http://www and the trailing slash at the end.
The Add Certificate panel creates a manual certificate. In order to use this function, you need to place an email address, then this certificate will be created and shown under Certificates menu. This function doesn't send/email the certificate to the recipient automatically.
If you require more features/functions, please visit the website for more information.