Identifier for Advertisers
The Identity for Advertisers (IDFA) is the individual and random identifier used by Apple to identify and measure iOS user devices. Resetting it somewhat regularly will make it much harder for advertisers to track you between iOS apps.
Reset IDFA on iPhone (iOS)
- Go to Settings > Privacy, tap Advertising, and then tap Reset Advertising Identifier.
Reset IDFA on Mac (Mac OS)
- Go to the Apple menu > System Preferences > Security & Privacy, click Privacy, select Advertising, and then click the Reset Advertising Identifier button.