My Apple ID was used to sign into iCloud via a web browser

First , don't click any link your received in whatever notification app , email, or message.

Go manually to the website appleid.apple.com and login then change your password, turn on authentication security to ensure that no access to your account without having you approve from another device you are using.

then ensure that you update security questions or even change it , also the photne numbe used as sign in approval.

last step is to ensure that no strange device registsered under your findMy app , delete immididately if you find unknown device listed in my devices in FindMy app.

Hello and welcome to the community 🤗

• If you have not signed in to iCloud recently and believe someone else may have accessed your account, go to Apple ID (https://appleid.apple.com) and change your password as soon as

possible.

• contact Apple Support

So I invite you to contact Apple Support