Hello @Farhan36
For what voltage that Kasa devices supports, please check details here :Q9. What voltages do Smart home products support?
General questions about Kasa Smart home products
Certain kasa smart devices are only sold US, and only has (US) version. May I know which country are you going to use the smart device? It is recommended to check local website and see if there is any smart switch listed or not, if not, that means that model is not sold in that area yet.
https://www.tp-link.com/home-networking/smart-switch/