function GetSaveFileName(const Prompt: String; var FileName: String; const InitialDirectory, Filter, DefaultExtension: String): Boolean;
Displays a dialog box that enables the user to select a new file. Returns True if the user selected a file, False otherwise. The name of the selected file is returned in the FileName string.
An example Filter: 'Text files (*.txt)|*.txt|All files (*.*)|*.*'
var
Filename: String;
begin
// Set the initial filename
Filename := '';
if GetSaveFileName('', Filename, '',
'Text Documents (*.txt)|*.txt|All Files|*.*', 'txt') then
begin
// Successful; user clicked OK
// Filename contains the selected filename
end;
end;