Open Settings on your phone
Tap Apps or Applications
Find and tap YouTube
Tap Uninstall
If Uninstall is unavailable, tap Disable
Confirm the action if prompted
On iPhone, press and hold the YouTube app icon
Tap Remove App
Tap Delete App
Confirm deletion if prompted
If YouTube is built into the phone, disable it through Settings
Remove YouTube from the home screen if needed
Restart the phone if the app still appears