The Passive Voice is more often used in English than in other languages.It is used:a) if the doer of the action is unknown, unimportant or obvious from the context.b) when the action itself is more important than the person who carries it out, as in news headlines, newspaper articles, formal notices, instructions, advertisements, etc.c) for reasons of tact or diplomacy
d) in such phrases as: It is said, it is allowed, it was declared, etc.(to make them sound impersonal and thus more direct)