Question

vani wrote a letter to the editor. she posted it yesterday. CHANGE INTO PASSIVE VOICE

Answer 1

A letter was posted yesterday written by vani to the editor.

In passive voice the place of the subject and the object will be changed also by and the past participle of the verb will be added

Answer 2

What is active voice?

It is a form or set of forms of a verb in which the subject acts  typically the person or thing performing this and which can take a direct object.

What is passive voice?

It is a form or set of forms of a verb in which the subject undergoes the action .Example of conversion from active to passive: Vani wrote a letter to the editor.

she posted it yesterday--- Change into passive voice.

Yesterday Vani posted a letter to the editor wrote by her orA letter was posted yesterday written by Vani to the editor.