Understanding the Sentence Structure
The original sentence, "Wherefrom had this mail been sent to you?" is in passive voice. To change it to active voice, we need to identify the subject, verb, and object within the sentence. In passive constructions, the subject receives the action rather than performing it.

Identifying the Components
- **Subject:** The mail
- **Verb:** Had been sent
- **Object:** You
In the active voice, the subject performs the action rather than receiving it.

Transforming to Active Voice
To convert the sentence to active voice, we can rephrase it as:
- "Who sent this mail to you?"
In this transformation, "Who" becomes the subject performing the action, and "sent" is the active verb, while "this mail" is the object being sent.

Steps to Change from Passive to Active Voice
1. **Identify the main verb** in the passive sentence.
2. **Find the doer of the action** (the agent) or replace it with an appropriate subject.
3. **Rearrange the sentence** so that the subject comes first, followed by the verb and then the object.

Importance of Active Voice
- **Clarity:** Active voice sentences are usually clearer and more direct.
- **Engagement:** They tend to engage the reader more effectively.
- **Conciseness:** Active voice often results in shorter, more impactful sentences.
By practicing these steps, you can effectively convert sentences from passive to active voice, enhancing your writing clarity and engagement.