De brief wordt geschreven.
English: The letter is being written.
'Worden' is used as an auxiliary verb in Dutch to form the passive voice. It shows that something is done to the subject, not by the subject.
You use 'worden' as an auxiliary verb in Dutch when you want to say that something is happening to someone or something (the passive voice). It is used for actions in the present or future.
De brief wordt geschreven.
English: The letter is being written.
Het huis wordt verkocht.
English: The house is being sold.
Ik word uitgenodigd.
English: I am being invited.
De auto wordt gewassen.
English: The car is being washed.