Understanding the two types of iCloud+ private email addresses

iCloud+ offers two types of "Private Relay" email addresses: user-created and those generated by the Hide My Email feature. These have different sending and receiving rules. User-created private emails use the icloud.com domain and forward emails to your primary address. Hide My Email addresses, using privaterelay.appleid.com, only forward emails from authenticated senders to prevent tracking and spam. Neither type allows sending new emails from the private address; replies are limited to specific app/service interactions. These are primarily for receiving forwarded emails.