Dial *67 before the phone number on most North American phones
Use #31# before the phone number on some carriers and countries
Enable caller ID blocking in your phone’s call settings
Turn off caller ID in the Phone app settings if available
Contact your mobile carrier to activate permanent caller ID blocking
Use a VoIP or calling app that supports hidden caller ID
Check local carrier and country codes for caller ID suppression
Note that emergency services and some toll-free numbers may still see your number