Can I use 4G/LTE in my iPhone 4S, please answer me!!

Google is your friend. Try to remember that in future when demanding answers with exclamation points:

https://www.apple.com/iphone/LTE/

GB

The iPhone 4S does not support LTE. If you are using AT&T, the phone may display 4G, but that is just AT&T saying you are using its fast 3G.