Dial *67 before the number on most phones in the U.S. and Canada
Use #31# before the number on some carriers and countries
Enable caller ID blocking in your phone settings
On iPhone, go to Settings > Phone > Show My Caller ID > turn off
On Android, open the Phone app > Settings > Calling accounts or Caller ID > hide number
Contact your carrier to request permanent caller ID blocking
Use a VoIP app or service with caller ID suppression
Check local laws and carrier rules before blocking your number