This command is accessible both in file management and in archive management modes. In file management mode it deletes the selected files and folders to the Recycle Bin, so you have the chance to restore accidentally deleted data. But in archive management mode the selected files and folders are deleted from the archive completely, without any possibility of restoring them later, so you need to be careful here. To run this command use either Commands menu , button "Delete" on the toolbar, Alt+D or Del keyboard shortcuts.
In file management mode you can also delete files permanently. Press Shift+Del instead of Del to avoid moving files to the Recycle Bin. Shift+Del command silenly deletes even files with read-only and system attributes and permits to delete files with non-standard names, such as with trailing spaces and dots. Usual Recycle Bin based delete can fail to process such names.