Is there syntax just like #region #endregion in Kotlin?

In IntelliJ IDEA (or Android Studio): yes, you can. You can do it by using //region and //endregion comments or by using //<editor-fold desc="..."> and //</editor-fold>.

Example:

//region name

fun someCode() { ... }
fun someMoreCode() { ... }

//endregion

// or

//<editor-fold desc="name">

fun someCode() { ... }
fun someMoreCode() { ... }

//</editor-fold>