This is much more critical than some people think. A tax ID number is your corporation or LLC’s separate tax identity. Whether it’s opening a bank account, setting up payroll, or filing a tax return, this number is THE number for all purposes. Here’s how you can get one (good luck to you) or here’s how you can get one (answered by me). Important note: you need some kind of tax identification to get a Tax ID Number. Usually that original identification comes in the form of an individual’s Social Security Number (usually the person forming the entity if it’s a small business). But foreign owners have a more difficult time doing this since they don’t usually have Social Security Numbers; in that case, they need to apply for an individual tax ID number, and then use that number to get the Tax ID Number for the corporation or LLC.