Hi, Im a Canadian, living in Canada and have partnered together with 4 US citizens/US residents to form a LLC based in California. We are a SaaS developer, with no earnings, to date. Do I need a US tax ID # now? I’m confused by the statement only needing to send in the Form W7 when actually submitting a tax return. I’m also concerned does one actually need to mail their Passport to the IRS offices??