I have foreign worker on my US payroll. Do I do payroll withholdings? Do I issue a W-2? He has no ITIN, does he need one to file federal tax return? He was in US 8 days.

I was told I need to get him to apply for either SSN or ITIN because his salary is paid out of US. He travelled to the US for 8 days

Deductions & credits

If the worker is not a US citizen, permanent resident nor resident alien, and is working abroad, he is not liable for taxes in the US. He would need to provide you with a form W8BEN. Once you have that form, you do not withhold any taxes from his pay. If you pay him before receiving the form, you need to withhold taxes. Only in that case would he need to apply for an ITIN To receive a refund for the withheld taxes 

https://www.irs.gov/individuals/international-taxpayers/tax-withholding-on-foreign-persons

Deductions & credits

The OP said the employee was in the US for 8 days.  Assuming that was for work, does the employee need to fill out a W-4 and a W-2 or 1042-S need to be issued?

If it was not for work, the employer should get a W-8BEN, right?

Deductions & credits

@bine22, Thanks for the response.  Do I have to withhold tax for the days he is on a business trip in the US?

Deductions & credits

if he earned money during that time, he would be liable for taxes on that money only. See here for details on withholding and reporting: <a rel="nofollow" target="_blank" href="https://www.irs.gov/publications/p515/">https://www.irs.gov/publications/p515/</a>    To be able to earn money while in the US, he needs to have a visa allowing him to receive money (a tourist visa wont do).

Deductions & credits

@bine22, thanks.  I have spoken to a tax accountant locally and now more confused because everything he pointed was straight from IRS.  So do I collect a W-8ECI and withhold or W-8BEN and do withhold?  I appreciate this forum as I get more layman answers here.