Several years ago, Apple made some changes to its Safari browser in which it would make it harder for advertisers to track you. Basically Safari came with a new smart cookie blocker where it would stop cookies from tracking users across multiple websites, thus reducing the chances of you seeing targeted advertisements.
Now it seems that with iOS 14, Apple will be making it even tougher for advertisers to track users by requiring apps to ask for user permission. This comes in the form of changes made to the Identifier for Advertisers (IDFA), which is a random device identifier tag that Apple assigns to devices. This feature is used by advertisers to track users without necessarily revealing any identifiable information about the person they are tracking.
However, like we said, iOS 14 has made some changes to the IDFA where it will now be fully opt-in. This means that when an app that contains ads uses IDFA for tracking, users will be greeted with a prompt in which they are informed that they might be tracked, and whether or not they agree to it.
As AppleInsider notes, Apple had previously actually allowed users to disable IDFA, but given that the option to do is embedded deep within the settings, it makes it less obvious and some users might not even know about it.