The Office of Global Programs provides basic visa advice for study abroad candidates. Whether you need a visa to visit a third country almost always depends on your nationality, not your status as a student in the U.S. You will have to look at the website of the embassy of the country you wish to visit to see their requirements for visitors. Columbia is conveniently located in New York City where you can easily visit the consulates from around the world if you do need to apply for a visitor visa.
The two most important requirements are to remain registered full-time every term, making normal progress toward your degree, and not to accept any employment, either on- or off-campus, without written permission from the ISSO, and, if necessary, authorization from the Department of Homeland Security (DHS). Be familiar with the information in Maintaining F-1 status. Under certain conditions status may be reinstated if lost for reasons beyond your control. You may also regain status by leaving the U.S.
Remember to have your I-20 on your person and not packed away in checked luggage since you go through inspection before claiming bags. That said, if you forget your I-20, you should ask the immigration official for an I-515 upon entry, which will allow your admission in F-1 status for 30 days. With an F-1 visa you are normally admitted to the U.S. For 'duration of status' (D/S,) but if you are missing the I-20 it is most likely you will be admitted for 30 days with an I-515.
If you are leaving the U.S. during your program of study, you need an unexpired passport, unexpired F-1 entry visa, and an I-20 which has a travel signature obtained from the International Students and Scholars Office (ISSO) on page 3 that is less than 12 months old at the time that you return. Please read Travel and Re-entry in F-1 Status for more information.
Interning and volunteering offer opportunities to gain experience, build your skills, and strengthen your resume. For unpaid work on or off campus such as volunteering or an unpaid internship, you may start right away and do not need OPT. You must be sure the position is unpaid for anyone (i.e. not just you because you want to take the job as a volunteer). Start by using these tools:
As an international student, it is essential that you fully understand your eligibility to work in the location of the internship or job and the process to gain work authorization. Eligibility to work considerations include:
CC and SEAS may grant up to 16 credits earned from Advanced Placement (AP), General Certificate of Education Advanced Level Examinations (A levels), the International Baccalaureate Examination (IB), and other national systems. Credit is typically awarded after the first year. A complete description of policies, credits, and/or exemptions can be found in the College and Engineering bulletins.
All international students in F-1 (and J-1) status are required to file at least one tax form if present in the US at any time in the previous calendar year—even if they had no US income. This process happens between January and April each year for the previous year. For example, 2013 taxes will be filed by mid-April of 2014. Students with U.S. income do pay taxes (taken out of their paycheck) and need to file taxes by April 15. Students without income (no tax has been paid) need to file by 15.