Work Must Be Related to Major Field
Regulations state that work done for OPT must be "directly related to the student's major area of study." If you have studied a double major and both majors are updated on your I-20, you may work in both or either major fields during OPT. You must work in the major field that is listed in your most recent program. You may only work in a field from a prior degree earned in the U.S. if you have been granted the OPT STEM Extension based on this prior degree.
The Student Exchange Visitor Program (SEVP) recommends that the student maintain evidence for each job documenting the position held, proof of the duration of that position, the job title, contact information for the student's supervisor or manager, and a description of the work (such as a job offer letter). We do not have a specific template for this documentation but it should include these details about the student's employment.
If it is not clear from the job description that the work is related to the student's degree, SEVP recommends that the student obtain a signed letter from his or her hiring official, supervisor, or manager stating how the student's degree is related to the work performed.
Work Must Be a Minimum of 20 Hours/Week
If you are on post-completion or STEM OPT you must work a minimum of 20 hours/week to maintain your F-1 status. You are allowed to be unemployed or work less than 20 hours/week for no more than 90 days during post-completion OPT or an additional 60 days during the OPT STEM extension period. There is no requirement of minimum employment hours during pre-completion OPT.