Accounts allow you to add in details of the organizations so that you can track your leads and deals better.
Delete an Account
Go to the Account tab and select the one you want to delete.
This will take you to the Account detail view. Click on 'Things You Can Do' on the top right corner of the accounts detail. Then select the 'Delete' option.
Once you click on 'Delete' you will see a confirmation dialog. Here you will notice a warning that if you proceed with deleting the account there will some references that will be removed and it will show how many entities will be affected. If you are sure you want to delete the account then click the 'Delete' button. This operation can not be undone.
To learn how to create or delete Accounts, please visit the following tutorials: