Voice, in a grammatical sense, applies to verbs. Voice expresses the relationship of the subject to the action. Voice can be active or passive. Active voice places the subject before the verb so the subject does the action (for example, Max drew the picture). Passive voice places the receiver of the action before the verb (for example, The picture was drawn by Max).
Voice, in a literary sense, is the distinct personality of a piece of writing. The writer's voice is the individual writing style of the composer, created through the way they use and combine various writing features including syntax, punctuation, vocabulary choices, character development and dialogue (for example, a scientific explanation may be written in ‘expert voice’).