If you use Gmail, or an alternative provider like Outlook, you might want to turn off iCloud email on your Apple hardware. This will save battery life on your portable devices, and get rid of unnecessary clutter from the Mail app too.
Here’s how it’s done.
Note that you can’t actually deactivate iCloud email within your account. Apple simply doesn’t allow this – if you activate iCloud for use with things like Photos and iCloud Drive, then you must have an iCloud email as part of it. All you can do is turn off downloading and sending of iCloud email on each of your Macs and iOS devices. The messages will remain on Apple’s servers, available for future download unless you explicitly delete them within the Mail app before following the steps below.
Open System Preferences, click the iCloud icon, and remove the check alongside Mail.
iPhone, iPad and iPod Touch
Open the Settings app, tap iCloud, and then deactivate the switch alongside Mail.
See the instructions above for iPhone because the Watch mirrors your iPhone’s email settings.