Verbs:Das Passiv im Präsens
Voice is a grammatical category that describes the relationship between a verb and its subject. Just like in English, this relationship in German can be active or passive. If the subject is acting, the voice is active, but if the subject is being acted upon, the voice is passive.
In the first example above, the subject (i.e., the man) acts upon the direct object (i.e., steals the lamb's lettuce). In the second example, the subject is the lamb's lettuce: it is acted upon when it is stolen.
The subject is not mentioned in the second example. Leaving the agent responsible for the action out (i.e., using the passive voice) indicates that the agent is obvious, or insignificant, or altogether unknown. The Fairy Tale police would have used the passive voice until the identity of the Täter (criminal) was certain, and they just wanted to enter into their blog the fact that some rapunzel went missing from the witch's magic garden ...
To state the agent in a passive construction, use the dative preposition von (by).
If the agent is an inanimate force (i.e., the weather) use the accusative preposition durch.
As you can see, the passive voice is formed with the auxiliary verb werden and the past participle of the main verb (i.e., stehlen => gestohlen in the examples above).
The passive voice uses all of the same tenses as the active voice, but the most frequently used tenses in the passive are the present, simple past, and present perfect tenses.
Das Passiv im Präsens
In the present tense, the auxiliary verb werden is conjugated in the present (i.e., wird, werden, etc.).