Question

he said to me "we are Mortal".change into passive voice​

Answer 1

Answer:

I have been told by him that we are mortal

Answer 2

I think it would be narration change not voice change. Because you give coatation.As your question I answer this.

1. "We are mortal" was said to me by him.

If it has ordered to change direct to indirect then you can do this

2.He told me they are mortal.

(Universal truth so no change of tense)