Written by the people who do the work. Structured as important steps, key points and reasons. Uses photos, screenshots and simple diagrams, words alone are rarely enough. Short and specific, one task per document. Posted at the point of use so operators can consult it without leaving the workstation. Owned by a named person who keeps it current.
This TWI-derived structure is the most reliable format for teaching work. Important steps are what to do. Key points are how to do it safely, correctly and to quality, the specific grip, angle, torque, sequence. Reasons explain why, because operators who understand why apply the standard judgment when unusual situations appear.
Work instructions are not written once and archived. Every Kaizen that changes a step must update the instruction. Every new deviation observed on the floor is an opportunity to improve the instruction. Regular reviews, often part of Leader Standard Work, keep the library honest. An outdated instruction is worse than no instruction because it teaches a method that no longer applies.
Work instructions are the operational backbone of standard work. Well written, kept current and actually followed, they make training faster, quality more consistent and improvement more sustainable. They are the difference between "this is how we do it" being an opinion and being a fact.
