Open the Settings app
Tap Sounds & Haptics
Under Sounds and Vibration, turn off Vibration options you want to disable:
Turn off Vibration for Silent Mode
Turn off Vibration for Ring Mode
To disable vibration for specific alerts:
Tap the alert type (e.g., Sounds and Vibration / Ringtone, Text Tone, New Mail, Calendar Alerts, etc.)
Turn off Vibration for that alert type
To disable system haptics:
In Settings, go to Sounds & Haptics
Turn off System Haptics (if available)