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, head over to your website's hPanel and locate the FTP Accounts menu in the Files section.
There you will notice two sections - Select Directory and Create a New FTP Account. Just select a directory that the account will be able to access, choose a username and a password for your account and you will be good to go! :)