When submitting Forms I864 or I134, an employment verification letter can help show that the beneficiary has adequate financial support. How do you ask your employer if they can sponsor your work visa after receiving an offer letter and completing joining formalities?In most cases, the process begins when the employer obtains an approved Application for Permanent Labor Certification from the U.S. Department of Labor (DOL). No need to call it out in cover letter? Apply to Secretary, Tax Preparer, Product Manager and more! US work visas, like the H1B and L1, need sponsorship from a US employer. Here's how the process works, and how much it costs. Employment verification letters prove that you or your sponsor can receive certain immigration benefits. Job Types: Full-time, Contract. A sufficient amount of information in the letter should be dedicated to describing the role that the sponsor plays in the company.