I485 questions, please help genome2003-12-14 18:55:00

I am filing I485 now (NIW approved). The I485 application requires an employment letter. Since NIW is not supported by the employer, why should I have this letter from the employer. Do I have to have this letter?
How and what should be written in the letter?

Thanks for all your help

需要证明你能够在经济上自立不会成为美国的负担呀。