A useful process document helps someone complete real work with fewer guesses. Its value comes from clarity at the moment of use, not from the number of pages written.
Start with a recurring task that causes confusion, rework or repeated questions. Documenting every activity at once can leave you with a library that nobody maintains.
Capture the minimum working version
Write the trigger, intended result, owner, necessary inputs and main steps. Add a definition of completion: what must be true before the work moves forward?
Include the most common exception and where to ask for help. If access to a system is required, describe how to obtain authorized access rather than embedding passwords in the instructions.
Test with someone who did not write it
Ask a colleague to follow the document during a real or representative task. Observe where they need additional context. Those questions identify gaps more reliably than polishing the wording alone.
For illustration, “send the onboarding email” may hide several decisions: which template, who confirms the start date, what information must be included and where the sent message is recorded. Explain those decisions where they occur.
Screenshots can help when an interface is confusing, but label them with a review date. A clear description of the intended action remains useful when a button moves.
Give the document an owner
Place the instructions where the work happens and name who updates them. Review the document when the process changes or when repeated questions show that it no longer works.