How can I just delete emails from my iCloud

When Apple ID is signed in iPhone Sign in with your Apple ID - Apple Support and mail box is turned as on Change your iCloud settings - Apple Support , the mails can be deleted directly from iPhone Delete emails on your iPhone, iPad, and iPod touch - Apple Support

They will be also deleted from iCloud.com when you view the mails from a web browser by signing in with Apple ID and password and account credentials of an iPhone .