Accounts allow you to add in details of the organizations so that you can track your leads and deals better.
Edit an Account
Go to the Account tab and select the one you want to edit. There are two options to edit an Account. The first one is to click on the edit button right below the Account logo (1) or by clicking on 'Things You Can Do' on the top right corner of the accounts detail and then click on 'Edit' (2).
This will display a window to edit the Account's information. When you are done with the changes, click the 'Save' button.
To learn how to create or delete Accounts, please visit the following tutorials: