Had is used for 2st, 2nd, and 3rd person, both singular and plural, and it always indicates some sort of past action. Had can be used as a main verb in the simple past tense to indicate possession, or with a helper verb to indicate other types of tenses.
- Main verb, past tense: Years ago, Emma had a car.
- Helper verb, present perfect: She has had a good career as a race car driver. (=She is still racing.)
- Helper verb, past perfect: She had had a good career as a race car driver. (=She has stopped racing.)