Causative Have And Get

Have

Have is a common causative verb. Instead of doing something ourselves, we "have" someone else do it instead. It has the following form:
The verb "to have" + object + past participle. For example:
- I had my jacket cleaned yesterday.
- Did you have your computer fixed?

Sometimes we use have as a causative verb when we intend to perform the action ourselves. For example:
- When will the report be ready? I'll do it by tomorrow morning.
- When will the report be ready? I'll have it done by tomorrow morning.

By using the causative the second sentence takes attention away from the doer of the action, and gives more attention to the action being done. It sounds polite and professional.

Get

Get is often used instead of have. For example:
- I got my computer fixed - I had my computer fixed. These two sentences mean the same thing.
- I got my jacket cleane. - I had my jacket cleaned. These two sentences mean the same thing.

Causative verbs are often used with negative experiences. In these situations it's more common to use have. For example:
- I had my wallet stolen. (I didn't actually cause my wallet to be stolen - someone stole my   wallet from me)
- She had her window smashed.

Source :

http://www.1-language.com/englishcourse/unit70_grammar.htm

Exercise 36: Causative Verbs

Use the correct form of the verb in parentheses in each of the following sentences.

1.      The teacher made Juan leave the room.

2.      Toshiko had her car repaired by a mechanic.

3.      Ellen got Marvin typed her paper.

4.      I made Jane call her friend on the telephone.

5.      We got our house painted last week.

6.      Dr. Byrd is having the students write a composition.

7.      The policeman made the suspect lie on the ground.

8.      Mark got his transcripts send to the university.

9.      Maria is getting her hair cut tomorrow.

10.  We will have to get the Dean signed this form.

11.  The teacher let Al leave the classroom.

12.  Maria got Ed washed the pipettes.

13.  She always has her car to fix by the same mechanic.

14.  Gene got his book published by a subsidy publisher.

 15. We have to help Janet to find her keys.