Generally, a citizen of a foreign country who wishes to enter the United States must first obtain a visa, either a nonimmigrant visa for temporary stay, or an immigrant visa for permanent residence.
Visitor visas are nonimmigrant visas for persons who want to enter the United States temporarily for business (visa category B-1), tourism, pleasure or visiting (visa category B-2), or a combination of both purposes (B-1/B-2).
If you are required to obtain a visa to enter the United States, it will likely be a B-1 visa because "NEXT Library" is a professional convention/conference.
There are several steps to apply for a visa. The order of these steps and how you complete them may vary at the U.S. Embassy or Consulate where you apply. Please consult the instructions available on the U.S. Embassy or Consulate website where you will apply.
For additional support feel free to contact NEXT Library conference organizers at:
email address: firstname.lastname@example.org
Chicago Public Library
400 S State St
Chicago, IL 60605