回複：移民局會核實國內人寫的reference letter嗎？

I was told by my lawyer that I need to provide the employment verification letter from all previous employers with company's letterhead. And you need someone to sign the letter. But they don't care who signs the letter, as long as the letter has company's letterhead on it. The employment verification letter has to confirm that you had the working experience before you were hired by the employer who is filing the application for you. And these skills are required for your current position.
Good luck!