Beyond the usual requirements — the qualifying corporate relationship, the qualifying employment period abroad, and special knowledge — offsite placement raises restrictions concerning who supervises the employee and whether the placement is essentially labour for hire. Those questions are fact-specific and need a licensed US immigration lawyer's assessment.
Describe the arrangement as it is
The temptation is to write the description that sounds most favourable. Resist it, because the client's own project documents, invoices, and communications describe the same arrangement and are unlikely to match a tidied version. Set out the supervision, the deliverable, and the pricing basis accurately, and let counsel work from the real facts.
Where the arrangement itself is the problem, changing it is a decision the business can still make. Two specific conditions apply where the employee will work primarily at a third party's premises, and they are worth stating so the business knows what it is being asked. The placement must not amount to labour for hire — that is, the arrangement cannot in substance be the supply of a worker to be controlled by the other company — and the petitioning employer must retain control and supervision of the employee's work rather than ceding it to the site owner.
Those are answered by how the engagement actually operates: who assigns tasks, who conducts reviews, whose procedures govern the work, and what the client is buying. Note as well that L-1B stay is capped at five years in total. Hypothetical example: a warehouse control systems specialist is to be embedded in a customer's implementation team for eighteen months, and the question of whose procedures govern their daily work is answered by reading the statement of work rather than by asking anyone's impression.