"Werden" is an important verb in German that is used in a number of different ways. It can be used as a main verb (meaning "to become") or as helping verb when constructing the future tense, passive voice, or subjunctive 2. This page talks about when and how to use "werden," along with a number of examples.
There are a few different situations where we use the verb "werden":
Use with a noun:
Use with an adjective:
As a main verb it means "to become."
Future 1: „Ich werde morgen zu dir kommen.“
Passive: „Der Kuchen wird gebacken.“
Subjunctive 2: „Er würde gern Millionär sein.“
When "werden" is used in these constructions, it doesn't have any meaning of its own. It is just used to signal what tense is being used. For more information on how to use "werden" in these situations, look at the individual pages on the future 1 , passive and subjunctive 2.
When do I use "worden" and when "geworden"?
When using the perfect tense with "werden" as the main verb (i.e. "He has become a teacher."), use "geworden."
When using the perfect tense in the passive voice (i.e. "The cake has been baked."), use "worden."