A DOS-formatted floppy does not appear on the Desktop without a PC Exchange control panel (part of System 7.5) installed and active.
The standard way of ejecting a floppy disk is to drag its icon to the Wastebasket (Trash). One can also eject a disk via the Put Away command in the File menu. Do not use the Eject Disk command in the Special menu, unless you wish to swap floppies (only for certain purposes).
Normally, an inserted floppy should come out when the computer is switched off.
In case of a problem, it is possible to manually eject a diskette by means of a straightened paper clip. See chapter 9 in the 030-5538 manual
here for details.
Jan