I am applying for Graduate school in US. I have 2 years working experience and i have 3 people ready from my company to provide me the letter of recommendation but as a whole the company will provide 1 universal letter with a letter head and the person individually cannot use it as it against companies policy. Should i go ahead with LOR of these person(with their official mail) and not without the letter?. Will it affect my application??
No one really cares if a LoR is on letter head. In fact a lot of letters simply get uploaded directly into a webform. I would, however, be concerned about the company policies. Many companies do not want their employees writing letters of recommendation since it opens the company up to potential law suits. My guess is the universal letter that the company will provide has been reviewed by the legal department. It will likely state your job title and your dates of employment and not much else and be completely useless for grad school admissions.
If your letter writers at the company follow this path, the letters will be awful. You need to make sure that they know how to write a good letter and are willing to.
Official letterhead is preferred, of course, but I think it would be a minor matter and easily explained. The content of the letter and what it says about you is far more important. Their email and physical address will connect them with the company.
But seek the people who can give you the strongest recommendation.