To facilitate the USCIS security checks, petitioners should provide a copy of the passport biographical data page (usually the page containing the passport holder's photograph) for each beneficiary of any type of petition or application filed with USCIS, except for large groups (over 25). These pages have a way of becoming illegible when faxed, so petitioners should try to get good, legible hard copies instead, or at least have the sender enlarge the copy before faxing. Not all beneficiaries will have a passport at the time of filing, however, nor are they required to do so. If a beneficiary lacks a passport at time of filing, note that fact in the petitioner cover letter or on the beneficiary list and, if possible, include a copy of another government-issued ID instead, such as a driver's license.
A salutary effect of obtaining this documentation in all cases, even those involving large groups, is that it enables the petitioner to copy data, including names, birth dates, etc., straight from the source. It is critical to eliminate errors in beneficiary information, lest there be a discrepancy between the I-797 approval notice and any ensuing visa application.