The passive voice is used when the focus is on the action being performed, rather than on who or what is performing the action.
In German, the passive is formed with the auxiliary verb werden and the past participle of the main verb.
The agent (who performs the action) is either omitted or introduced with the preposition von (by).
Formation
Present Passive: werden + past participle
Example: Das Buch wird gelesen. The book is being read.
Past Passive: wurde + past participle
Example: Das Buch wurde gelesen. The book was read.
Examples
Das Haus wird gebaut.
The house is being built.
Der Brief wurde von ihm geschrieben.
The letter was written by him.
Das Essen wird serviert.
The food is being served.