In IOS14, you need to get permission to get the IDFA. A plugin that invokes a native dialog asking for permission to do so.
A plugin that asks for permissions to use IDFA in Flutter apps
Getting Started. #
<key>NSUserTrackingUsageDescription</key> <string>This identifier will be used to deliver personalized ads to you.</string>
For functionality from IOS14, you need to use the IOS14 Simulator and XCODE 12.