In most employment-based cases the attorney who prepares the petition is retained and paid by the company, and you appear on the signature pages as the beneficiary. That is normal, it is permitted, and in the ordinary case it works fine, because the employer wants the petition approved as much as you do. The arrangement is usually described as dual representation, meaning the firm represents both parties on the same matter with written consent from each. The interesting question is not whether to accept it. It is which specific things you should read, request, or copy before the interests diverge.
1. The consent letter, read all the way to the withdrawal clause
The document that sets this up goes by several names: a dual representation letter, a joint engagement letter, a conflict waiver. Whatever it is called, it says who the client is, what the firm will do, and what happens if the company and the beneficiary come to disagree. Read the last part carefully, because it usually provides that the firm will continue representing the employer and stop representing you. That is the standard result, not a slight. Knowing it in advance changes what you say to that attorney and what you keep to yourself.
2. Who holds the privilege, and what that means in practice
Communications inside a joint representation are generally privileged against the outside world and generally not privileged as between the two clients. In plain terms, what you tell the firm about a prior visa refusal, an unauthorized work period, or an arrest can reach the employer, because the employer is also the client and the firm has duties to it. Nobody is hiding this from you; it is written into the letter you signed. If you have a fact you need analyzed before anyone at your company hears it, that conversation belongs with an attorney you retain yourself.
3. The complete copy of every filing, taken as it goes out
Ask for a full copy of each submission at the time it is filed, not two years later when you need it. That means the form, the supporting letter, the exhibits, the receipt notice, the approval notice, and any response to a request for evidence. For labor certification cases you also want the recruitment documentation and the certified application; the Department of Labor oversees that step and its records outlast most jobs. Some of these documents are the employer's property and some are yours. Receipt and approval notices with your name on them belong in your own file, permanently.
4. The priority date, and what survives a departure
If the job ends, the petition does not simply follow you. An I-140 approved for at least 180 days generally keeps its priority date usable by a later employer, and an approved petition can retain validity for a change of employer in some circumstances, but the mechanics turn on dates, category, and status. The employer can also withdraw the petition. A careful reader writes down the receipt number, the priority date, and the classification while everything is calm, because a former employer's attorney is under no obligation to look them up for you afterward.
5. The moment separate counsel earns its fee
Independent representation is worth paying for in a narrow set of situations, and probably not otherwise. Those situations: a layoff or resignation while a petition is pending; a competing offer that requires a portability analysis; a fact in your history that could support a finding of misrepresentation; a green card process where the terms of your continued employment are being negotiated against the timing of your filing; and any point where the company's lawyer tells you they cannot advise you. A consultation of an hour or two, paid at the firm's ordinary rate, usually answers the question.
6. The paper trail you keep yourself
Keep your own file, offline and complete: passport pages, every I-94 record, every approval notice, pay records covering each period of sponsorship, and the correspondence in which the company's attorney told you what they were filing and when. It takes an hour to assemble and it removes almost every dispute about what actually happened. Beneficiaries who do this move employers faster, because the next attorney can price and plan the case from documents rather than from memory.
Dual representation is not a compromise you are forced into; it is an efficient arrangement with a clearly marked edge. Learn where that edge sits, and you will know the day you cross it.