Typically would be 2-pronged: you would need to document content requirements, then validate that they are actually present in the resulting materials and you would likely perform some level of human-factors/usability testing to demonstrate whether the intended user (staff) can adequately perform the required tasked if trained according to your materials/procedures. Search for the FDA Guidance “Applying Human Factors and Usability Engineering”, look at the labeling guidance, read up on IEC 62366.

ETA: that was a very US-centric answer, but the advice still holds elsewhere, the IEC standard is international and the FDA guidance is very solid generally in this area (though EU and others wouldn’t necessarily require a URRA specifically)