EdX certificates are delivered online through edx.org. EdX does not offer physical copies of certificates by mail or email. Once course grades are finalized, if you earned a certificate you will see a link to view this on your dashboard.
A link will also appear in your profile and on the progress page in the course.
Most self-paced courses issue certificates as soon as you have a passing score.'
You can print out your certificate using the printer icon in the upper right when viewing your certificate:
Many operating systems will also allow you to print to PDF if you would like to save an electronic copy to your computer.