Think “no passive voice” as the rule for business; most of business writing is in active voice. In business, we want action.
The short way to see passive voice is to notice when two verbs are used in the same sentence. For instance….have purchased…. The first verb is a form of the verb “to be.” Rewrite your sentence without the “have.”
Passive voice is appropriate for the Indirect approach and in academic style writing.
Successful Business Communication 