Question

they were helping us change into passive voice​

Answer 1

Answer:

It’s “we were helped by them”.

In the sentence “they were helping us” (which is in the active voice) the pronoun “they” is the agent (the ones doing the helping), and also the grammatical subject of the verb “to help”.

“Us” is the recipient (the ones receiving help) and the grammatical object of the verb.

To construct the passive voice, you make the recipient of the action into the grammatical subject, and the agent of the action into the grammatical object.

Wikipedia article about the passive voice: 

Answer 2

Answer:

They are helping a picture passive and active voice change