When you sign up for a Facebook account or add a new email address to your existing account, Facebook will send an you an email. This way, we can make sure that you own the email address connected to you account. To confirm this, all you need to do is click on the link in the email.
If you didn’t sign up for a Facebook account and received a confirmation email in error, you can deactivate the account in question by clicking the link at the bottom of the email.