Its most helpful for begginner level student.

2. ACTIVE AND PASSIVE VOICE
Voice is the form of verb which indicates
whether subject does something or
something has been done to it. There are
two types of voice:
 Active voice
 Passive voice

3.  Active voice : When the subject is the doer or
agent of the action, the verb is the active voice.
Example: The boy makes a kite.
Subject + verb + Object
 Passive voice: When the subject is the target or
receiver of the action, the verb is said to be in the
passive voice.
Example: A kite is made by the boy.
S(Object) + H.V + M.V3 + By + O(Subject)

4. Word order of both Active voice and Passive
voice
ACTIVE VOICE: The boy makes a kite.
PASSIVE VOICE: A Kite is made by the boy.

6. When the active voice is changed to the
passive voice:
 1.The primary auxiliary verbs do, does, or
did do not appear in the passive voice.

7.  2. The auxiliaries verb has, have, and had are
used in the passive, but they change their from
according to the number and person of the
passive subject.
ACTIVE VOICE PASSIVE VOICE
Have you invited them? Have they been invited by
you?
Have You finished the Work? Has the work been finished
buy you?
Have you invited him? Has he been invited by you?

8.  3. The question words when, why, where, how,
and what do not change their position of the
beginning of the sentence while changing it in
to passive voice.
Example:
ACTIVE VOICE PASSIVE VOICE
What did he say? What was said by him?
Whom did you invited? Who was invited by you?
Who did this? By whom was this done?

9.  The verb will, Shall, can or may do not change
their position of the beginning of the sentence.
Example:

12. ACTIVE VOICE PASSIVE VOICE
She has finished her work. Her work has been finished by her.
She has not finished her work. Her work has not been finished by
her.
Has she finished her work? Has her work been finished by her?

18. To change imperative sentences The word “Let”
is added before
Sentence in Passive Voice. Auxiliary verb “be” is
added after object in sentence in passive
voice.
Let + Object + be + Past participle