You should have your passport available while completing your DS-160.
If you have already made travel arrangements, you should have your travel itinerary available.
Dates of your last five visits or trips to the United States, if applicable, and international travel history for the past five years.
Information about your current and previous education and work history may be required.
Some applicants may be asked to provide additional information depending on the intended purpose of travel.
Provide your SEVIS ID from your I-20 or DS-2019, as well as the address of the school/program at which you intend to study.
A copy of your I-129 form is required for H-1B, H-2, H-3, CW1, L, O, P, R, and E2C visa categories.
You will need information about your employer, including the employer's address.