Ford fiesta Zetec 2003?

Hi Central locking does no mean remote locking. which is what you are talking about.
the two are entirely different a central locking just uses a standard key like you have been given.
the remote locking is a wireless key which may be fitted as an extra when the car was new before it was delivered when new.

As per your other answer, but, there are kits you can buy that can convert your car to remote locking. The downside is usually you need a fob on your key ring with a couple of buttons so it ends up being bulky. You ought to have thought about that one before you bought the car ....