Payroll registers, records of employment, dated employment letters describing duties, and travel history are what actually establish it. A current job description proves what she does now; the requirement is about a continuous year already served with the qualifying organization within the three years before filing.
Reconstruct the year from records that were not written for this purpose
Documents created for an immigration file are read more sceptically than documents created for other reasons, which is why payroll data, T4 slips, group benefit enrolments and internal appointment memoranda carry weight. Together they establish who employed her, without interruption, and over what dates. Add a letter from the Canadian company that describes the duties across that period in operational language, ideally signed by someone senior to her.
Where she attended American sites during the year, keep the travel record, because periods of employment inside the United States for the same employer do not count toward the qualifying year even though brief visits do not interrupt it. If the employing entity was renamed or amalgamated during the period, provide the corporate document showing that continuity, since a gap in the employer's identity looks like a gap in her employment.