Question

passive form help the helpless

Answer 1

Active voice :
Help the helpless.
Passive voice :
Let the helpless be helped.

Answer 2

active voice:

A form and set of forms of a verb in which the subject is typically the person as well as thing performing the action and which can take a direct object.

we are given active voice sentence Help the Helpless in which 'helpless' is the noun.

Passive voice

A form as well as set of forms of a verb in which the subject undergoes the action of the verb

The correct passive voice sentence will be The helpless should be helped.