Hello LatteG,
Thanks for using Apple Support Communities. It sounds like you’re having trouble with the keyboard on your iPhone. We’re happy to provide some steps that may help.
To start, make sure you’re running the latest iOS version. Updates often fix software issues you may be experiencing:
Update your iPhone, iPad, or iPod touch - Apple Support
Should the issue persist, remove any third-party keyboards you may have installed. We also suggest removing and re-adding the Emoji keyboard. You can find steps here:
About the keyboards settings on your iPhone, iPad, and iPod touch - Apple Support
If the behavior continues after trying the above, the last thing you’ll want to try is reinstalling the iOS. While this shouldn’t remove any information from your iPhone, it’s a good idea to have a backup handy:
How to back up your iPhone, iPad, and iPod touch - Apple Support
To reinstall the iOS, follow the steps in the article 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.