Open Settings
Tap Sounds & Haptics
Tap Haptics
Choose Always Play, Play in Silent Mode, or Never Play
Tap any sound type under Sounds and Haptic Patterns
Tap Vibration
Select a built-in vibration pattern or tap Create New Vibration
Tap and hold to create a custom vibration pattern
Tap Stop when finished
Tap Save
Name the custom vibration
Tap Done
Assign the custom vibration to a contact in Contacts
Open the contact
Tap Edit
Tap Ringtone or Text Tone
Tap Vibration
Select the custom vibration
Tap Done
Repeat for other contacts or alert types as needed