I noticed I have two Facebook account but I would like to know how to delete one of them.
You can permanently delete your Facebook account by following the instructions on the Facebook support site:
If you don't think you'll use Facebook again, you can request to have your account permanently deleted. Please keep in mind that you won't be able to reactivate your account or retrieve anything you've added. Before you do this, you may want to download a copy of your info from Facebook. Then, if you'd like your account permanently deleted with no option for recovery, log into your account and let us know.
When you delete your account, people won't be able to see it on Facebook. It may take up to 90 days to delete all of the things you've posted, like your photos, status updates or other data stored in backup systems. While we are deleting this information, it is inaccessible to other people using Facebook.
Some of the things you do on Facebook aren’t stored in your account. For example, a friend may still have messages from you even after you delete your account. That information remains after you delete your account.