I know nothing about cars, so last month I repaired my car at a garage.
I know nothing about cars, so last month I had my car repaired at a garage.
I can’t cut my own hair, so I cut it at the hairdresser’s next to my house.
I can’t cut my own hair, so I have it cut at the hairdresser’s next to my house.
Use have + object + past participle when you arrange for somebody else to do something for you.
The form of have changes according to the tense: ‘I have my hair cut every month.’ ‘I had my car repaired last week.’ ‘I’m going to have the kitchen painted.’
This structure is also called the causative have.
Check our grammar lesson on have something done.