Predictive emojis not working on iPhone 12 IOS15.4.1

HI Dancala,

Welcome to Apple Support Communities. We understand that you're having an issue with predictive emojis on your iPhone after an update. We'd like to help.

What happens when you try to view an emoji when texting? Do you not see the corresponding emojis in the predictive Menu bar or is the word not highlighting to allow you to change it to the emoji? What steps have you tried from online? Knowing exactly what you're not seeing can be helpful in allowing us to make recommendations. Were these the steps: Use emoji on your iPhone, iPad, and iPod touch - Apple Support

Have you closed Messages and restarted your iPhone? Those small troubleshooting steps can sometimes resolve issues like this. Give that a try!

Close an app on your iPhone or iPod touch - Apple Support

How to close an app

iPhone X and later

1. From the Home Screen, swipe up from the bottom of the screen and pause in the middle of the screen.

2. Swipe right or left to find the app that you want to close. 

3. Swipe up on the app's preview to close the app. 

Restart your iPhone - Apple Support

How to restart your iPhone X, 11, 12, or 13

1. Press and hold either volume button and the side button until the power-off slider appears.

2. Drag the slider, then wait 30 seconds for your device to turn off. If your device is frozen or unresponsive, force restart your device.

3. To turn your device back on, press and hold the side button (on the right side of your iPhone) until you see the Apple logo.

Hope that helps!