1Details.kt.diff

 class OrderDetails {
-    var fullName: String = ""
-        set(value) {
-            field = value.split(" ").joinToString(" ") { it.capitalize() }
-        }
+    var fullName by CapitalizeDelegate()

-    var city: String = ""
-        set(value) {
-            field = value.split(" ").joinToString(" ") { it.capitalize() }
-        }
+    var city by CapitalizeDelegate()
  
-    var coupon: String = "NO COUPON"
-        set(value) {
-            field = value.toUpperCase()
-        }
+    var coupon by UppercaseDelegate()
}

2Delegates.kt

class CapitalizeDelegate : ReadWriteProperty<Any?, String> {
    private var formattedString: String = ""

    override operator fun getValue(thisRef: Any?, property: KProperty<*>): String = formattedString
    override operator fun setValue(thisRef: Any?, property: KProperty<*>, value: String) {
        formattedString = value.split(" ").joinToString(" ") { it.capitalize() }
    }
}

class UppercaseDelegate : ReadWriteProperty<Any?, String> {
    private var formattedString: String = ""

    override operator fun getValue(thisRef: Any?, property: KProperty<*>): String = formattedString
    override operator fun setValue(thisRef: Any?, property: KProperty<*>, value: String) {
        formattedString = value.toUpperCase()
    }
}

3Main.kt

fun main() {
    val details = OrderDetails()
    
    details.fullName = "john doe"
    details.city = "pune"
    details.coupon = "abcdef"

    println(details.fullName) // prints "John Doe"
    println(details.city) // prints "Pune"
    println(details.coupon) // prints "ABCDEF"
}