Call Windows format dialog
One of the ways to format disc, is calling standard Windows format dialog. Use ShellExecute function for this.
ShellExecute(Application.Handle, 'Open', // path to the rundll32.exe file. For example: 'C:\Windows\System32\Rundll32.exe', 'Shell32.dll,SHFormatDrive', 'C:\Windows', SW_SHOWNORMAL);