Can someone log into your iCloud and see your messages?

Can someone log into your iCloud and see your messages? If someone logs into your Apple ID on the web, they can’t see or send your iMessages. However, if on an Apple device, they can. All iMessages you send and receive, through either your Apple ID or phone number, past and future, will be viewed on another device once someone logs into your Apple ID.

If someone logs into your Apple ID on the web, they can’t see or send your iMessages. However, if on an Apple device, they can. All iMessages you send and receive, through either your Apple ID or phone number, past and future, will be viewed on another device once someone logs into your Apple ID.