To say a job is finished now but you don't say who did it, use has / have been + the past participle. The thing comes first.
has / have been + the past participle
Someone has fixed the computer. → The computer has been fixed. (it works now)
They have solved the problem. → The problem has been solved.
They have signed the papers. → The papers have been signed.
Try it: Workers have built the bridge. Turn this around so the bridge comes first. (Leave out the word you don't need.) Answer: The bridge has been built. — It's finished now and you don't say who did it, so has been + the past participle: The bridge has been built. "Build" is the base verb, the passive needs the past participle built, so leave it out.
has been for one, have been for more
Use has been for one thing (he, she, it). Use have been for more than one (they) or with I, you, we. The been and the past participle stay the same.
Someone cleaned the room. → The room has been cleaned.
They sold all the tickets. → All the tickets have been sold.
They promoted him. → He has been promoted to manager.
Not "The house was been built." — say "The house has been built.". It's has been, not "was been". For one thing, use has been.
Try it: They have sold all the tickets. Turn this around so the tickets come first. (Leave out the word you don't need.) Answer: All the tickets have been sold. — Tickets is more than one, so use have been + the past participle: All the tickets have been sold. "Has" is for one thing, so leave it out here.
hasn't / haven't been + the past participle
To say a job is not finished, put n't on has / have: hasn't been or haven't been + the past participle. We often add yet to say it may still happen.
Nobody has finished the report. → The report hasn't been finished yet.
They haven't cleaned the rooms. → The rooms haven't been cleaned yet.
No one has paid the bill. → The bill hasn't been paid.
Not "The report hasn't finished yet." — say "The report hasn't been finished yet.". Don't drop been. "hasn't finished" says the report did the finishing. Use hasn't been + the past participle.
Try it: Nobody has finished the report. Build the negative: the report isn't finished. (Leave out the word you don't need.) Answer: The report hasn't been finished yet. — For the negative, put not on the first word: hasn't been + the past participle: The report hasn't been finished yet. "Finish" is the base verb, the passive needs the past participle finished, so leave it out.
Has / Have + it + been + the past participle?
To ask if a job is done, put has / have first: Has or Have + the thing + been + the past participle? The thing goes in the middle.
The computer is fixed? → Has the computer been fixed?
The tickets are sold? → Have the tickets been sold?
The papers are signed? → Have the papers been signed?
Not "Has been the computer fixed?" — say "Has the computer been fixed?". Keep the thing in the middle: Has + the computer + been + fixed?
Try it: Someone has built the bridge. Build the question: is the bridge finished? (Leave out the word you don't need.) Answer: Has the bridge been built? — For a question, put has first, then the thing, then been + the past participle: Has the bridge been built? "Build" is the base verb, the passive needs the past participle built, so leave it out.