Reply
Do you mean you want to apply for I-140 based EAD (e.g. you reported your employer illegal conducts and thus, you were fired)? If so, technically, you can apply for the I-140 EAD by yourself. But the justification for I-140 EAD (i.e. why you think you are qualified for the I-140 based EAD) is somewhat complicate, so I would suggest you to hire or consult an immigrant lawyer to help you.