Identify relevant records that explain the actual work and employment relationships; the appropriate submission depends on the case.
Resolve gaps in the employer’s description
If the offer omits customer duties, obtain an accurate explanation. Do not invent a contract or customer commitment to make a provisional assignment appear confirmed. Hypothetical example: a wildlife biologist receives a letter that names a project but omits the employer’s supervision of field reporting.
Build a document map from employer to customer: signed offer, duty description, supervision evidence and any agreement that explains why work occurs away from the employer’s site. The key record settles who controls the assignment and what professional output is expected. Put dates and version numbers on each item, then compare them for mismatched locations, duties or pay.
Trouble often begins when a polished support letter says one thing while a statement of work says another. Obtain a corrected explanation rather than guessing at the gap. Credentials and citizenship evidence answer separate questions, so neither should be used as a shortcut for proving the employment relationship.