A verb is "a word or phrase that describes an action, condition or experience" (Cambridge University Press, n.d., para. 1).
When using the active voice, the subject of the sentence does the verb to the object.
E.g., I wrote the paper (subject=I, verb=wrote, object=paper).
When using the passive voice, the subject of the sentence is acted upon.
E.g., The paper was written by me. (subject=paper, verb=was written, object=me).
To help you identify the passive voice in your writing, keep in mind that
the verb phrase will always include a form of be, such as am, is, was, were, are, or been. The presence of a be-verb, however, does not necessarily mean that the sentence is in passive voice. Another way to recognize passive-voice sentences is that they may include a "by the..." phrase after the verb; the agent performing the action, if named, is the object of the preposition in this phrase. (Purdue University, n.d., para. 3)
Using the active voice makes your writing clearer and more to the point. It helps to avoid wordiness because usually the active voice is more direct and requires fewer words to communicate the message.
For more information regarding the active versus passive voice, please refer to The OWL at Purdue: Active and Passive Voice, The OWL at Purdue: More About Passive Voice and the Writing Centre's Active Versus Passive Voice YouTube video. For links to instructions on how to turn on MS Word's grammar and style options that will check a document for a variety of issues, including passive sentences, please see Check Grammar, Spelling, and More in Word.
Cambridge University Press. (n.d.). Verb. Cambridge dictionary. Retrieved February 24, 2021, from https://dictionary.cambridge.org/dictionary/english/verb
Purdue University. (n.d.). More about passive voice. Purdue Online Writing Lab. https://owl.purdue.edu/owl/general_writing/academic_writing/active_and_p...