https://www.irs.gov/publications/p519#en_US_2020_publink
You must furnish a taxpayer identification number if you are:
An alien who has income effectively connected with the conduct of a U.S. trade or business at any time during the year;
An alien who has a U.S. office or place of business at any time during the year;
A nonresident spouse treated as a resident, as discussed in chapter 1; or
Any other alien who files a tax return, an amended return, or a refund claim (but not information returns).
