To transform a sentence from passive voice to active voice, you'll typically identify the subject, the action, and the object. In passive voice, the subject receives the action, while in active voice, the subject performs the action.
For example, consider the passive sentence: "The book was read by Maria."
In active voice, it would be: "Maria read the book."
If you provide a specific sentence in passive voice, I can help you rewrite it in active voice and explain the information contained in both forms.