Previously in 2021, the U.S. Department of State (DoS) announced waivers for in-person visa interviews for academic visas (such as F1, M1, and certain J1 categories). This means that applicants applying for these visas in their home country could submit their entire application to the U.S. Embassy via postal mail instead of attending the visa interview in-person.

The DoS has now announced that they will expand interview waivers for the L1 visa, and other U.S. visa categories, until the end of 2022. This is in an effort to clear backlogs and processing delays due to the effects of COVID. The new categories now elligible for interview waivers are L, O, P, Q, H1, H3, and H4 visas. The applicants must be applying from within their country of birth or residence. In addition to the F1, M1, and J1 visa interview waivers, this will remain in effect until December 31, 2022.

There is also speculation that interview waivers could be applied to B1 and B2 visas due to increasing demand. If an interview waiver is permitted, the applicant must submit their application package, along with their passport, as per the directions of the consulate website with whom they are applying.

Sources:
Expanded Interview Waivers for Certain Nonimmigrant Visa Applicants
Important Announcement on Waivers of the Interview Requirement for Certain Nonimmigrant Visas