The perfect form is used when an action has occurred and has ended, except in the present tense where it may be still under consideration.
In the perfect form will use an auxiliary verb + the past form of the main verb (or the past participle sometimes known as Verb 3)
The present perfect is used when an action began in the past yet is still relevant. It’s created by using the present tense of have/has + past form of the verb (known as (the past participle or verb 3).
The past perfect tense is used to show that one action has finishes before a second action begins. When words like before and after are used this indicates that the past perfect tense may be in use. The past perfect is created by using had + past participle.
The future perfect is used when an action will be finished before something else happens in the future. It’s made by using will + have + the past participle.