With to have you can use the verb construction
1 to have someone do something
2 to have something done
In both constructions you have a two-part object after to have, an accusative and an infinitive/past participle. This two-part object corresponds logically to an independent sentence:
The gardener cuts the hedge. Mr Brown is the cause for the action. (See example 1a.)
In Latin such a construction was called accusative with infinitive (aci) and it was a very frequent construction and in English it is equally often used.
1a Mr Brown, the owner of the house, had the gardener cut the hedge.
Here Mr Brown orders the gardener to cut the hedge.
The normal verb construction is accusative (acc) + to-infinitive. Some frequently used verbs have acc + bare infinitive: to make/have/bid/let someone do sth and after verbs of perception as to see/watch/etc someone do sth
2a Mr Brown had the hedge cut ( by the gardener).
Of course, the passive variant is possible, too.
Two-part objects with acc and infinitive (with/without to) or gerund/participle or past participle are a chapter of its own in the grammar of verb constructions. In grammars this grammar chapter is often strewn across the whole grammar so that you seldom get a clear view of this type of verb constructions.