certificate; certification document
An official document certifying that a person or organization meets certain standards, has completed a course, or has been recognized for an achievement. Often used in formal, administrative, or educational contexts.
Upon completing the training, a certificate will be issued.
This certificate proves that he is a certified public accountant.
免許証 is a license permitting the holder to engage in a regulated activity (e.g., driver's license), whereas 認定証 certifies that a standard has been met or a qualification achieved, without necessarily granting legal permission.
Compound of 認定 (にんてい, 'recognition, authorization') and 証 (しょう, 'certificate, proof'). The word follows a standard pattern for official documents in Japanese.