Summarize:

You'll usually find this gear-shaped icon on your home screen or in a folder.  Before you can use the Bitmoji keyboard on your iPhone or iPad, you must install the Bitmoji app, create an account, set up a Bitmoji avatar, and link the avatar to Snapchat. You can only use Friendmoji with Snapchat friends who also use Bitmoji. This means the person you want to create Friendmoji with must also link their Bitmoji character with Snapchat. It's in the third group of settings. It's in the fourth group of settings. It's the first option. A list of installed keyboards will appear. If you already see Bitmoji in this list, you can return to the home screen. If not, continue to the next step to add the Bitmoji keyboard. It's at the bottom of the list. You may have to scroll down to see it. This adds the Bitmoji keyboard to your keyboard list. This allows the Bitmoji keyboard to insert Friendmoji and other Bitmoji characters into your conversations. Follow these steps to do so:  Tap the back button to return to the Keyboard list. Tap Bitmoji in the list. Slide the "Allow Full Access" switch to the On (green) position. If prompted to do so, follow the on-screen instructions to confirm this change. This will definitely work with your iPhone/iPad's built-in messaging app, but you may also have luck in other messaging apps. You can do this by tapping the outline of a globe near the bottom-left corner of your keyboard until you see Bitmoji characters. It's the two overlapping faces near the top-right corner of the Bitmoji list. If it's your first time using the keyboard, tap Continue when prompted to allow access to Snapchat. Scroll through the list and tap the person you want to include in your Friendmoji. You'll see a message that says "Bitmoji copied. Now paste it!" This pastes the selected Friendmoji to the typing area. Now you can add additional text to your message or just send it as-is. If you're using Messages, the Send button a blue-and-white arrow at the bottom-right corner of the typing area. It may look like a paper airplane in other apps.
Open your iPhone or iPad's Settings . Scroll down and tap General. Scroll down and tap Keyboard. Tap Keyboards. Tap Add New Keyboard. Tap Bitmoji. Give the Bitmoji keyboard full access. Open conversation in Messages or another messaging app. Select the Bitmoji keyboard. Tap the Friendmoji icon. Select a Bitmoji friend. Tap the Friendmoji you want to add. Tap and hold the typing area and select Paste.