Hi fyrefly13,
Thanks for using Apple Support Communities. It sounds like you’re having trouble with your phone freezing when you use the emoji keyboard. I’m happy to help.
To start, make sure you’re running the latest iOS version:
Update your iPhone, iPad, or iPod touch - Apple Support
If that doesn’t help, I suggest reinstalling iOS. While this shouldn’t delete any information from your device, it’s a good idea to make a backup first:
How to back up your iPhone, iPad, and iPod touch - Apple Support
To reinstall iOS, follow the steps below under the section labeled “Put your device in recovery mode and set it up again”:
If you can't update or restore your iPhone, iPad, or iPod touch - Apple Support
Take care.