I want to know how secure is my iCloud email.

I want to know how secure is my iCloud email. I have Outlook email and I can see my recent activity and I can see when is the last time I used my email and a lot of options that I don't see in iCloud email. I am worried because I use it for all of my accounts and it has my contacts numbers, notes, and email. I am afraid that it may be hacked or something like that.