If you cannot find the email folders from your Webmail, they might not be enabled on your mail server.
You may enable them from the Folder Actions (Cog icon) within webmail when you are logged in.
***Note that this is for RoundCube
First, login to your webmail (www.yourdomain.com/webmail) using your full email address and account password.
One logged in, click on the “Folder Actions” (Cog icon) on the lower left corner of your screen and go to Manage Folders. The system will automatically give you the Folders section on the left pane of the window. From there, you can check the boxes of the folders you wish to be displayed on your webmail.