Question

He is going to post the letter (change into passive voice) ​

Answer 1

The sentence can be changed into passive voice as follows:

The letter is going to be posted by him.

• In the sentence mentioned in the question, 'He' is the subject and 'the letter' is the object.
• To change the sentence into passive voice, 'he' will be changed to 'him' to make it the object of the passive voice sentence. 'The letter' will become the subject of the passive voice sentence.
• The main verb of the sentence will be changed into past participle.

Answer 2

Question. He is going to post the letter (change into passive voice)

Answer. A letter is going to be posted by him.