Received Notification that someone was signing into my account

Can you still access the account? If so then change the password immediately. Once this is done then turn on 2-step authentication which will alert you whenever someone tries accessing your account again by asking for confirmation that it is you (or not) wishing access.

If not then you can recover the account here:

https://support.apple.com/en-us/HT204145

If you believe your Apple ID has been compromised: https://support.apple.com/en-us/HT204145

You should log into your Apple account & change the password immediately. I would also recommend setting up 2-step authentication.

got notification someone signed into my cloud account. i want to look into that