ref – http://www.differencebetween.net/language/difference-between-has-and-had/

A verb phrase contains a verb which is a word that conveys action or state of being and is usually modified or changed according to tense, aspect, mood, and voice. It must agree with its subject or object. It shows this agreement in the third person singular present tense forms of verbs that are added with ‘s’ to form its regular form.

Verbs can be ‘intransitive,’ which means that it only has one subject, or ‘transitive,’ which means that it has a subject and a direct object.

Has

‘Has’ is a transitive verb because it requires a direct subject and one or more objects.

It is the third person singular present tense of the verb ‘have’

For example, in the sentence: ‘Jane has pimples,’ ‘pimples’ is the direct object of ‘has.’

Examples:
1. He has a dog.
2. He has a huge house.
3. She has a pen in her hand.
4. She likes him, but she has a boyfriend.
5. The cat has the mouse by the neck.
6. The weather has turned cold.
7. Everyone (third person) has hopes and dreams.

‘Has’ can also be used with a past participle to form the perfect tense like in the sentence: ‘He has gone.’ It can also be used in a verb phrase and idioms.

Had

‘Had,’ on the other hand, is the past tense of the transitive verb ‘has.’ It is the third person singular past tense and past participle of the verb ‘have.’ It is synonymous with the word ‘taken,’ which means ‘deceived’ like in the sentence: ‘He has been had.’

Other examples:

1. She has a cat. (third person present tense ‘has’)

2. He had a dog but it died. (third person past tense ‘had’)

3. He has a nice car. (third person present tense ‘has’)

4. She had a nice car, but it was wrecked. (third person past tense ‘had’)

5. He has her by the hand. (third person present tense ‘has’)

Summary:

1. ‘Has’ is the third person singular present tense of ‘have’ while ‘had’ is the third person singular past tense and past participle of ‘have.’
2. Both are transitive verbs, but ‘has’ is used in sentences that talk about the present while ‘had’ is used in sentences that talk about the past.
3. ‘Has’ is synonymous with the words: own, possess, occupy, and hold while ‘had’ is synonymous with the word ‘taken.’