How can I check the hidden email generated for an specific app?

Hey Backwardslegal,

Welcome to Apple Support Communities. You can find out which email addresses are being used for which apps using the following guidance from Create and manage Hide My Email addresses in Settings on iPhone - Apple Support.

You can create and manage Hide My Email addresses in Settings Go to Settings > [your name] > iCloud > Hide My Email, then do any of the following:

• Create a Hide My Email address: Tap Create New Address, then follow the onscreen instructions.

• Deactivate a Hide My Email address: Tap an address (below Create New Address), then tap Deactivate Email Address. After you deactivate the address, it no longer forwards emails to you.

• Change which personal email address to forward to: Tap Forward To, then choose an email address. Options consist of addresses that are available with your Apple ID.

• Copy a forwarding address to use elsewhere: Tap an address (below Create New Address), touch and hold the Hide My Email section, then tap Copy. To immediately use that address elsewhere, touch and hold in a text field, then tap Paste.

Kind regards.