Vanguard index fund investment for foreigners

Is anyone here who is US nonresident alien investing in Vanguard index fund? Can you tell me what I am supposed to do to invest in this fund? Tax treatment for foreigners? Any issues that I need to consider?

Thanks in advance.

Apply for a tax ID number first. Not many US firm will open an account for your if you don’t have a valid US Tax ID number. Having that said, very few (I stress very few) firm are willing to do an NSR (non-resident alien) account without an tax-ID number, but good luck!

Thanks a lot.