The @Autowired annotation helps us to connect constructors, fields, and setter functions. This annotation injects object dependencies. 

Here's the sample code of how to use @Autowired on a property:

class User(val name: String,
            val id: String)

class Users{
    @Autowired
    val user:User ?= null
}

Here's the sample code of how to use @Autowired on a property:

class UsersForAutowired{
    private lateinit var userDetails: UserDetails

    @Autowired
    fun setUserDetails(userDetails: UserDetails){
        this.userDetails = userDetails
    }

    fun getUserDetails(){
        this.userDetails.getDetails()
    }
}

The content of UserDetails.kt is as follows:

class UserDetails{
    init {
        println("This class has all the details of the user")
    }

    fun getDetails(){
        println("Name: Naruto Uzumaki")
        println("Village: Konohagakure")
    }
}

The output of the project will be as follows:

This class has all the details of the user
Name: Naruto Uzumaki
Village: Konohagakure

We can utilize the @Autowired annotation on properties to dispose of the setter functions. When we pass values of autowired properties utilizing <property>, Spring will allocate those properties with the passed values or references. So with the utilization of @Autowired on properties, the UsersForAutowired.kt file will become as follows:

class UsersForAutowired{
    init {
        println("UsersForAutowired constructor." )
    }

    @Autowired
    private lateinit var userDetails: UserDetails

    fun getUserDetails(){
        this.userDetails.getDetails()
    }
}

The result will be as follows:

UsersForAutowired constructor.
This class has all the details of the user
Name: Naruto Uzumaki
Village: Konohagakure

You can also apply @Autowired to constructors. An @Autowired constructor annotation demonstrates that the constructor should be autowired when making the bean. This should be the case regardless of whether any <constructor-arg> components are utilized when configuring the bean in the XML file. 

Here is the modified content of UsersForAutowired.kt:

class UsersForAutowired @Autowired constructor(private var userDetails: UserDetails) {
    init {
        println("UsersForAutowired constructor.")
    }

    fun getUserDetails() {
        this.userDetails.getDetails()
    }
}

The result will be as follows:

This class has all the details of the user
UsersForAutowired constructor.
Name: Naruto Uzumaki
Village: Konohagakure