icloud unlock

iCloud ID is the same as your Apple ID.

If the Apple ID is yours then try here: https://iforgot.apple.com

If the Apple ID is not yours then there's nothing you can do except you can get help from the previous owner.

Don't post your email address, these are user public forums - I've asked the hosts to remove it.

To reset an account's password : http://iforgot.apple.com

https://support.apple.com/HT201487