Your F visa will affect your employment opportunities and how long you can stay in the US.
On-campus Work: F-1 visa students who are maintaining a full time course of study can work on campus part time (20 hours per week maximum) during the academic year and full time during the summer months and any periods when school is not in session. No special permission or document is needed to give you permission to work on campus.
Off-campus Work: F-1 visa students must obtain prior authorization from the INS before working off campus. It generally takes the INS about three months to reply to any application for off campus work.
Duration of Status: An F-1 student’s permission to stay is called a "Duration of Status." It appears on the I-94 (your permit to stay in the U.S.) as D/S and relates to the expected date of program completion. Students must file for an extension of program at least one month before this date expires.