Icloud access on different devices.

Read this document if you think your Apple ID has been compromised. --> If you think your Apple ID 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 --> See who has access to your iPhone or iPad - Apple Support

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

Related materials:

Personal Safety User Guide

Personal Safety User Guide - Apple Support

> open the Table of Contents

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

If Some one. Has your Apple ID credentials They can see a lot of Things, Yes. I suggest that you change your Apple id password to prevent unwanted Access