Every course on edX.org, including those which are "self-paced" will have an end date. To earn a certificate on the verified track you will need to have a passing score by the end date.
Where is the end date posted?
Before you enroll, if the course will end within a year the end date is indicated above the Enroll button. You can read more here.
On the course homepage, you can find the end date under Important Dates labelled Course ends.
On the Dates tab, you can find it listed on the bottom.
Where's the course homepage?
To navigate to the course homepage from your dashboard, click the title of the course.
To navigate to the course homepage from any page within the course, click the Course tab in the course's navigation menu.
Where's the Dates tab?
To navigate to the dates tab, from any page within the course, click the Dates tab in the course's navigation menu.
In most courses it will still be possible to view the archived course contents after the end date, however the course staff will no longer provide support in the forum, it will not be possible to earn a certificate and some assignments and other contents may be removed.