Question

Passive voice of who has sent such an email?

Answer 1

this type of email is sent by whom

Answer 2

Passive voice of, “who has sent such an email” will be, “By whom was such an email sent”.

This difference in sentence structuring is due the fact that in Active Voice Sentences, the Subject is the Center of attention or focus whereas in Passive Voice sentences, the attention shifts to the actions performed by the Subject.