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.
If the end date is approaching soon or if the end date has passed, you can view the end date on the course homepage under Upcoming Dates or under the Dates tab. On the mobile app, you can check the Dates tab.
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.