This wikiHow teaches you how to update the emoji selection on your iPhone by updating your system software, which has emoji updates associated with it.
Steps

Step 1. Connect your iPhone to a charger
When installing system updates, it's best to keep your iPhone fully charged.

Step 2. Connect to a wireless network
You must be connected to a wireless network before installing system updates as they can be quite large and go through limited data plans quickly.

Step 3. Open your iPhone's settings
You'll find the Settings app on one of your home screens. It may be in a folder labeled "Utilities."

Step #4. Scroll down and tap on General

Step 5. Tap on Software Update

Step 6. Tap Download and Install if an update is available
If no update is available, the message 'Your software has been updated' will be displayed.
- If your device is up to date have the most recent emoji updates available.
- Older iOS devices don't get a newer system, so no emoji updates. For example, the iPhone 4S will no longer receive system updates and will not receive any emoji released after iOS 9.3.5.

Step 7. Wait for your update to be downloaded and installed
This can take from 20 minutes to over an hour, depending on your connection speed and the size of the update.
Your iPhone will reboot during the installation process and the Apple logo will be displayed as it installs

Step 8. Open an app where you use your keyboard
After the update is installed, you can check for your new emoji characters by opening your keyboard.

Step 9. Tap on the emoji button
You'll see this when the on-screen keyboard is open, to the left of the space bar. It looks like a smiley.
- If you have multiple keyboards installed, you may need to hold down the Globe button to select "Emoji."
- If you don't see the emoji keyboard, you may need to enable it. Tap Settings → General → Keyboard → Keyboards → Add New Keyboard → Emoji.

Step 10. Find your new characters
It may not be immediately obvious which characters are new as they are not highlighted anywhere. You will find the new characters mixed with the old ones in the corresponding categories.