If you need to rename a folder change the entry in the Name: field. Act on new/unread mail in this folder is enabled by default on new folders, it allows notifications about new mail that arrives in the folder. Uncheck this option on folders like SPAM and trash that you do not desire notifications.
When replying to messages in this folder, check Keep replies in this folder if you want the replies to be stored in this folder rather than into the default configured sent-mail folder.
Check Hide this folder in the folder selection dialog if you do not want this folder to be shown in folder selection dialogs, such as the Jump to Folder and Move Message to dialogs.
By default new folders use the default identity. Uncheck Use default identity and select a new one from the Sender identity drop down menu. See Identities configuration for information on Identities. Replies to messages that were sent directly to you will still default to the message's “To” address if an according identity is found.
If you have groupware, you can change the contents e.g. calendar, notes, etc. of the folder in the Folder contents: drop down box.
If you share the folder with other users, you can Share unread state with all users which will show the same unread state for all users.
