Ordinary sentences describing the duties, the title as it is used in practice, the reporting line, the dates or duration of the work, and the qualifications the employer relied on in hiring. The internal code can remain alongside, but it should not carry the description.
Write for a reader outside the company
A useful test is whether someone with no knowledge of the employer could read the letter and describe the job back. Names of internal systems, team acronyms, and product codenames fail that test unless they are explained. Keep the language factual rather than promotional, and make sure any credentials mentioned are ones the professional can actually document.
The degree, the transcript and course descriptions that show the biological content, together with the employer letter. Compare the revision against every draft letter and form, replace obsolete versions, and retain a short explanation if the change is material or could look inconsistent. An evaluation may be needed when an institution outside Canada, Mexico and the United States issued the degree, and professional licensing is a separate inquiry. Bring the statement of work or detailed employer letter, the corporation’s records, the diploma and the experience evidence.