A more thorough explanation:

A clearance card is a document given by an employer to an employee who is leaving their job. It includes information about the duration and nature of the employment, as well as the reasons for leaving. However, it is important to note that a clearance card is not necessarily a recommendation.

For example, if an employee is leaving a job due to poor performance or misconduct, their clearance card may reflect this information. On the other hand, if an employee is leaving on good terms and has performed well during their employment, their clearance card may reflect positive feedback.

Clearance cards are often required by future employers as a way to verify an applicant's work history and to ensure that they left their previous job on good terms. They can also be used as a reference for future job applications.