At minimum, the role identified by profession, a specific description of the professional duties, the party receiving the services, the remuneration arrangement, and a defined engagement period. Supporting letters can add context but should not contradict the agreement's terms.
One consistent description across every document
Where a signed agreement, a supporting letter, and an internal description differ, the discrepancy invites questions that a consistent file avoids. If the agreement is drafted commercially and describes deliverables rather than professional duties, ask for an accompanying letter stating the profession and duties without contradicting the contract. Do not remove activities that genuinely form part of the role.
Combining the most favourable sentences into a fictional position would weaken the evidence rather than establish the listed profession. If the statement of work describes workflow redesign and system specification while the letter calls the applicant a project coordinator, the profession is in doubt and the application can be refused on that inconsistency alone. TN requires Canadian or Mexican citizenship, prearranged professional work, and satisfaction of the chosen listing; it cannot support US self-employment.
If an exhibit must be redacted, preserve enough context to show who issued it, what it verifies, and how it relates to the prearranged US job.