If you are a non-U.S. citizen or non-U.S. national, and you're working in the United States, this information may help you with any petitions you are planning to file. It also may help you avoid status problems.

Please note that this article does not constitute legal advice.

1: Your I-94, not your visa, governs your length of stay

Do not confuse your visa with your I-94 document. The former controls the period of time during which you may enter the United States (subject to final approval of an immigration official at the U.S. port of entry). Once you have entered the United States, the visa associated with that entry has no further connection with your U.S. stay. In fact, that visa actually can expire, and as long as you remain in the U.S., that expiration has no effect on the legality of your stay.

The document that governs the length of your U.S. stay as a non-immigrant is your I-94 document. If you came to the U.S. as a student, in F-1 status, you received your I-94 at your port of entry. If you later received H-1B status via a change of status while staying in the U.S., your I-94 was attached to the bottom of your I-797 notice of approval. That document tells you when you must leave the U.S. If your I-94 departure date field has the notation "D/S," which stands for "duration of status," as long as you maintain the conditions of that status, you are permitted to remain in the U.S.

2: You need to use an acceptable version of a USCIS form

Always be sure that the form you are working on for submission to United States Citizenship and Immigration Services (USCIS) is either the current form or an acceptable earlier version of that form. Regulations and statutes will change from time to time, and forms must change as a result. For this reason, double-check each hardcopy form you are using at this Web site. It will tell you the current version of that form and whether earlier versions are acceptable. This recommendation applies regardless of whether you are submitting forms yourself or whether a lawyer is doing so for you. Lawyers and their staff can overlook this matter, so if you have any doubts, double-check yourself.

3: You should tell USCIS if you move

Most foreign nationals must tell USCIS their new address if they move and must do so within 10 days of their move. Report the new address via form AR-11, available at the USCIS Web site. Foreign nationals in F-1 status (i.e., students) may meet the reporting requirement by telling their designated school official (DSO).

4: Your OPT might be FICA and Medicare exempt

If you are being paid during your optional practical training (OPT) period, take a careful look at your pay stub. If your employer is withholding FICA (known better as Social Security) and Medicare taxes from you, the employer might be incorrect, because you might be exempt from FICA taxes. These taxes amount to 7.65% of your salary. In addition, your employer must pay an equal 7.65%. Because individual situations might vary, consider consulting a qualified tax professional for further guidance.

5: Unemployment period is measured in CALENDAR days, not business days

While you are in OPT, you are normally limited to 90 days of unemployment. If you are enrolled in the 17-month extension because your field of study was science, technology, engineering, or mathematics (STEM), your overall unemployment limit is 120 days. Note that in both cases, according to USCIS, these periods are calendar days, not business days.

6: There's a trick to determining whether you're STEM-eligible

Some fields of study are clearly STEM-eligible, while others might not be. For example, a friend who graduated with a degree in environmental science said she thought she was not eligible for STEM because her degree was M.A. rather than M.S. When I gave her the following advice on checking to make sure, she discovered otherwise and was so happy she bought me a Starbucks.

On page 3 of your I-20 document, near the top, you'll see the name of your field of study. To the immediate left of this name is a code number called a "classification of instructional program" (CIP) code. This code, NOT the name of your field -- and not whether the degree is "arts" or "science," or anything else -- determines STEM eligibility. Once you know your CIP code, compare it to the information at the Web site of United States Immigration and Customs Enforcement (ICE). This site has a page of CIP codes that are STEM-eligible.

7: When to apply for STEM

If you are STEM-eligible, you may apply at any time during your original one-year period for the extension. That is, you need not request it at the time you apply for OPT. In fact, you need not apply for the extension at all. Keep in mind that there is a fee for requesting the extension, and there are issues related to the timing of any intended H-1B petition (see below). If you have applied for the extension on time (i.e., if you applied prior to the expiration of the original OPT) and are awaiting a decision, you may continue to work even if your original OPT has expired in the meantime.

8: Factors to consider regarding OPT to H-1B transition

You might want to stay in F-1 OPT status for a longer time, primarily because you save money by possibly being FICA and Medicare exempt. However, the longer you stay in F-1 status, the greater the chance that the H-1B cap will be filled and the longer you will need to wait to begin your green card process. Because of visa delays and the risk of being denied entry upon leaving and returning to the US, I advise F-1 holders to delay the beginning of their green card process until they receive H-1B status.

In other words, you must weigh the short-term benefits of tax savings versus longer-term benefits of an earlier green card priority date and avoiding issues with the H-1B cap.

9: H-1B LCA is not a "labor certification"

Do not confuse an H-1B labor condition application (LCA) with a green card labor certification. In most cases, the former is vastly simpler than the latter. In most cases, your H-1B employer need not advertise or recruit for your H-1B position before offering you the job. All that employer has to do, in most cases, is certify that you will be paid at least the higher of actual or prevailing wage.

This certification is usually simpler than the advertising and recruiting activities connected with a green card labor certification.

10: Your immigration attorney and you can be in different places

Because immigration is a federal matter, not a state one, you can retain an attorney even if that person is in another state. To represent you before USCIS, that attorney must be admitted to the bar of, and in good standing in, any state of the U.S. or of the District of Columbia. In other words, your attorney can be, but need not be, admitted to the bar of the state you are in.