To register a sole proprietorship in New York City, you need to print and fill out this form: the X201 Certificate.
This is an official Certificate of Conducting Business under an Assumed Name for Individual.
Note that an Assumed Name Certificate (aka X201 form) must be filed with the clerk of the county in which the business is conducted ONLY IF you are operating under a name other than your own name.
In my situation, I am starting a new business named “Museum Hack.” I wanted to be able to refer to the company directly (and not myself) in certain paperwork and banking documents.
Blumberg Legal Forms says:
To help avoid rejection by the County Clerk’s Office, try a simple Internet search of the proposed name to see if other companies in your area use this name. Alternatively, in may counties (excluding New York County*), you may leave the name field blank and fill it in by hand at the Clerk’s Office after your proposed names have been checked on the county database for conflicts.
You will need additional certified copies of the form to open a bank account and to conspicuously display the form at each place of business.
This is part of our series of posts about starting a business in New York City.