Emojis are an incredibly popular way of sending visual emoticons on the iPhone. For easy access, use the Emoji keyboard.
When typing out a message, tap the smiley face icon towards the bottom left of the keyboard and the emoji icons will appear. When you’ve finished adding them, choose the ABC icon to return to your text-based keyboard.
This should be active by default, but if it’s not: open the Settings app, select General, Keyboard, followed by Keyboards. Select Add New Keyboard…, find the Emoji option, and tap to add it.
If you speak more than one language then you can add more keyboards. Open the Settings app, select General, then Keyboard, followed by Keyboards. Select Add New Keyboard… and choose from the available options. Now when typing tap the globe icon to cycle through them. Tap and hold the globe icon to quickly see all available keyboards and tap the one you want to use.