Question

The letter had just posted change the passive vioce

Answer 1

Answer:

in the given sentence, "the letter has been posted", the sentence is in passive voice. The sentence is also gender implied, since the subject is not mentioned in the passive voice. It can be either male or female.

Answer 2

$\huge\underline\mathcal\red{Hello Mate}$

$\huge\underline\mathfrak\blue{ANSWER....!!!!!!}$

It is already a PASSIVE Voice.