I quickly launch my UC Browser and made some googling, there I got to know how to enable it.
Now i opened my iPhone Settings–>General–>Keyboard–>Keyboards then I tapped Add New Keyboard
Which gave me list of Keyboard languages to add, I then chose the Emoji
When am done adding the Emoji, I then moved back to my WhatsApp and made a move to type something which the keyboard appeared then I tapped on the globe symbol to show me the smiley as shown below
And Yaaaaaaaaaaaahhhhhhhhhhhhhhhhoooooooooooo! I found my smileys and can use it
This worked for me and should also work for you 🙂