COVID-19 contact tracing involves four key steps:

Contact identification: it involves case investigation to identify all persons who have had contact with a confirmed case.
Contact listing: it is registering all persons considered to have had contact with a confirmed case.
Contact follow up: involves looking for signs and symptoms of COVID-19. It should be done for 14 consecutive days starting from the last date of exposure. Follow up can be active (requesting contacts to report their health status regularly) or passive (providing information), depending on the risk and resources.
Contact discharge: Contacts should be removed from the follow-up list when one of the following criteria is met:

A contact finishes his/her 14 days of follow-up.
A contact becomes a case and moved to a case list.
Subsequent investigation leads to the person being re-classified as a non-contact.
Subsequent investigation leads to the linked case being reclassified as a non-case.