You use "HAS" in 3rd person.
e.g.: She has a dog
He has brown eyes
The doy (it) has a ball
"HAVE" with the other personal pronouns
e.g.: I have a dog
We have an English book
You have long, black hair
"HAD" you use in past
e.g.: She had a dog when she was a child
We had English class yesterday morning
He had short hair at school
You had an interesting book, but you lost it.
"HAD" is the past of "HAVE" and "HAS" and you use with all personal pronouns.