Good question! Like many questions, the answer really depends on the particular situation.
Job shops and similar "short-run" operations usually have a "traveler" (often tucked in a transparent plastic folder to protect from dirt and damage) which contains ALL the details of the job order (blueprint, purchase order, inspection sheets, etc.)
The traveler travels with the job as it passes through various work stations to the final shipping desk.
Organizations which manufacture a single product often keep a copy of the specific work instruction for the work station in one of two places, depending on the complexity of the work instruction and the skill and experience of the worker.
- A simple process run by an experienced worker can probably get by with keeping the work instruction in a drawer at or near the work station.
- A complicated work instruction with a revolving work force might require posting the steps in prominent view for the worker to follow in an attempt to "mistake proof" the process.
If you tell us a little more about your exact situation, we may have some suggestions for what would work best in YOUR operation.