What is the ruling on writing receipts and invoices for companies that operate in forbidden fields (such as music or tobacco), submitting audited financial statements to them, writing the company's name in audit contracts, or sending emails concerning them to the tax authority? Is this considered aiding in the forbidden, and what is the ruling on the money received from this work?

There is no objection to working in the company as long as the majority of its work is auditing the accounts of entities with permissible activities, provided that one refrains from auditing the accounts of entities with prohibited activities. If you are unable to refrain, it becomes obligatory to leave work in the company unless there is an extreme necessity. If you remain in the job without necessity, the portion of your salary corresponding to the prohibited work becomes unlawful for you.