Evidence about the skills themselves and about the labour market for them: training records, the length of time the skills take to acquire, descriptions of the specific systems involved, and an employer statement explaining why the position is essential to this enterprise's operations rather than generally useful.
Describe the skill, then describe why this business needs it
Two halves of the record do different jobs. The first documents what the applicant can actually do, ideally through training certificates, equipment-specific qualifications, and a record of systems commissioned or maintained. The second is written by the employer and explains why the enterprise cannot readily operate without the position — what the equipment or process is, what happens when it is mismanaged, and how the business has handled the function until now. Employers often write this section in praise rather than in facts, which weakens it. Where the skills are widely available in the United States, the claim becomes harder, and it is better to know that early. All of it should be reviewed by a licensed adviser before it is presented anywhere.
The business file should let a reader trace the enterprise from ownership through expenditure to current operations. Collect formation records, ownership proof, contracts, invoices, bank transfers, payroll material, and a business plan that explains why the operation is more than a marginal livelihood. Capital must be committed beyond easy reversal and exposed to business risk, not merely promised. Hypothetical example: A mobile veterinary-imaging business has paid deposits for equipment but can cancel every order without consequence. The deciding records are the contracts and cancellation terms, because they show whether the money is truly committed.