var
  F: TextFile;
  S: string;
begin
  AssignFile(F, 'FILENAME.TXT');
  Reset(F);
  while not EOF(F) do
  begin
    Readln(F, S);
    V1 := Copy(S, 1, 3);
    V2 := Copy(S, 4, 6);
    ...
  end;
  CloseFile(F);
end;