Question

change into passive voice , he wrote a letter to his friend

Answer 1

A letter was written to his friend by him. 

Answer 2

Active voice:-  He wrote a letter to his friend.

Passive voice:- A letter was written to his friend by him.

• Passive voice structure is a systemic voice structure that is available in many languages.
• In the paragraph with the action word, the programmer identifies the subject or patient of the main action - that is, the person or thing that makes the action or situation has changed.
• Transforming the active concept of a verb into a verb is a process of reducing valence ("the process of removing transformation"), because it dynamically converts a dynamic concept into a dynamic concept.