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Good morning. To set up your Washington sole proprietorship in New York you would first have to obtain the office space in the county in which you would want to operate. If uou will not have a physical presence then you would need an address from where you would be in NY. After you have the address you must go to the County Clerk in the county your business is located and then file a "doing business creticate" with the clerk. They will then give you a certificate. Your next step would be to obtain a sales tax Id number from the NYS Department of Taxation,online at www.tax.ny.gov. The final step would to be to obtain a tax ID "EIN" number from the IRS, which can be done online at www.irs.gov. After you complete these three steps you can legally run your business in New York.
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