Open your device Settings
Go to General
Tap Transfer or Reset iPhone
Tap Reset
Tap Reset Keyboard Dictionary
Enter your passcode if prompted
Confirm the reset
Open Settings
Go to System
Tap Languages & input
Tap On-screen keyboard
Select your keyboard
Tap Clear data or Clear typing data
Open Settings
Go to System
Tap Language & input
Tap Virtual keyboard
Select your keyboard app
Clear its data or reset its dictionary
Open the keyboard app settings
Find Dictionary, Personalization, or Text correction
Delete learned words or clear personal data
Turn off predictive text if needed
Restart your device