You must register and set up an @icloud.com email address if you want to start using iCloud Mail.
To Login to your account:
On any computer go to iCloud.com. This is the fastest way to check your mail, because you can access it from anywhere on any device
You can also download iCloud for Windows here if you prefer to access the service through the desktop application
To sign in on your Mac first update to the latest macOS version, go to system preferences, select iCloud, enter your Apple ID and password,click Sign in
On your iPhone, iPad, or iPad Touch go to settings, tap Sign in, enter your Apple ID and password. Don't forget to first update your device to the latest iOS version before trying to access your account
Apple does not offer an iCloud app for Android yet, but you can access iCloud.com through any mobile web browser to check your email from there
Forgot your Apple ID or password? No problem, recover your Apple ID here