There are two methods to delete or deactivate your account
1. deactivate(temporarily)
2.permanently delete
To deactivate your account follow the steps:
1.login to facebook.com
2. Then go to your account then select settings.
3.now select security tab and you will see the deactivate option.
select deactivate to deactivate your account.if you want to reactivate your account then simply login to facebook.com to activate your account if you want to delete facebook permanentlythen click the following link to delete.