How do I secure my iCloud Mail account?

While it is unclear exactly what you are describing, I can offer these points:

• If someone knows your Apple ID Password, they can send an email from your iCloud account. Change your Apple ID Password.
• If the email came from a different provider, then you would need to change the password with them.
• If someone knows the Passcode to your device, they can use it to send the email.
• Do you have a record of this email in your Sent folder?

Read this document if you think your Apple ID has been compromised. --> If you think your Apple Account has been compromised - Apple Support

For iOS 15 or earlier, if you want to see if anyone else has access to your device or accounts, click here --> Checklist 1: Limit device and account access - Apple Support

For iOS 16 or later see how Safety Check on iPhone works to keep you safe. Safety Check for an iPhone with iOS 16 or later - Apple Support

Use the information in this document to check your Apple ID device list to find where you're signed in --> Check your Apple Account device list to find where you’re signed in - Apple Support

Related materials:

Personal Safety User Guide

Personal Safety User Guide - Apple Support

> open the Table of Contents and review the articles

A document with general information about security and your Apple ID --> Security and your Apple Account - Apple Support

Contact Apple for help with Apple ID account security. This page provides country-specific Apple Support contact information ➞ Contact Apple for support and service - Apple Support

Xeso4ka wrote:

I'll try to figure it out myself.. well, and a joke for the sake of brilliance - your personal photos in iCloud? It's like a private repository on GitHub... until someone forks it. 💬✅

Don't forget the any data stored on an internet server can be accessed by anyone that knows your password. This also includes any financial/banking websites. That is why it is important to have secure passwords and always use Two Factor Authentication if it is available in your region. Never reuse passwords or use them on multiple accounts and is also a good idea to change them periodically.

If you think your Apple ID has been compromised, start here:

If you think your Apple Account has been compromised - Apple Support