This will depend on the delivery service the retailer is using.
A good proportion of courier's are now using a tracking service.
Retailers will typically provide the unique tracking code with your
order details, and then you can use the code on the courier's website
to track the status of it's shipping. Parcelforce is an example
of one UK courier who provides a tracking service; an example of
their tracking code is "AA00010019GB". You can usually
track orders globally and nationally within the United Kingdom.
An error can be produced if you use the tracking code before the
goods have entered into the courier's despatch service,