To create a new folder, tap the top left corner to reveal the list of folders, and tap Create Folder on the bottom left.

Another option is to go to More (o o o) | Various Account Settings | Choose Account | Folder Management | Create Folder

Note: TypeApp shows all IMAP folders from the server provider you have connected to.

In POP3 accounts folders are not synchronized. Other folders you create locally will not be available from other clients.TypeApp_Tip_Create_Folder