Multiple FTP accounts are great if more than one user will be accessing your website's files. You can also restrict the new account's access by allowing it to access only specific folders.
To create a new FTP account, open Hosting → Manage → FTP Accounts section:
On the bottom of the page, you will be presented with Create a New FTP Account section. There you will be able to specify a custom directory, username and password for your new FTP account:
NOTE: If you wish for your FTP account to have access to the root folder of your website, leave /public_html as the directory.
Once created, FTP accounts can be easily removed in List of Active FTP Accounts section: