edX certificates are delivered online through edx.org. edX does not send physical copies of certificates by mail or email. Once the certificate is available, if you earned a certificate you will find a link to view this on your dashboard.
A link will also appear in your profile and on the progress page in the course.
Self-paced courses issue certificates as soon as you have a passing score. In instructor paced courses, the certificate will be available on the date indicated on the course homepage under Upcoming Dates.
You can print out your certificate using the printer icon in the upper right when viewing your certificate:
You can also print to PDF if you would like to save an electronic copy to your computer. You can find steps to print to PDF in this article.