The document discusses the past participle verb form. It explains that the past participle is formed using "have/has" plus the past tense form of the verb. It also notes that regular verbs form their past participle by adding "-ed" or "-d" like the past tense, while irregular verbs are irregular in both past tense and past participle forms. Finally, it provides an overview of the present perfect and past perfect tenses, which both use the helping verb "have/has" plus the past participle to indicate completed actions in the present, past or future.