An iCloud account that comes with an Apple device grants you access to a unique email address. While you might be used to using this email account in the Mail app on your iPhone, iPad, or Mac, you can actually access iCloud Mail from any web browser (including Chrome and Microsoft Edge).
To block email in iCloud so that selected messages go to your Trash folder, you'll need to set up a rule, and you'll need to do it in a web browser. To set up a rule in iCloud Mail, go to Settings → Rules and select Add a Rule. Then, create a rule so that messages from a specified sender go to the Trash.
In iOS 10.2 or earlier, go to Settings > iCloud > [your name] > Password & Security > Change Password. Enter the passcode to your device. Enter a new password and then enter it again to verify the password.
Select the iCloud Mail alias you would like to turn off or delete and select Disable alias or Delete alias. 3. Once you have finished click Done to complete the process.