Policy, procedure, protocol, guideline or standard
What follows is a summary of this article: https://apolitical.co/solution-articles/en/what-does-policy-actually-mean-anyway
A policy addresses the ‘who’, ‘what’, ‘where’ and ‘when’ through clear, concise, non-negotiable formal statements that provide overarching guiding principles and rules. People in scope of the policy are expected to adhere to the policy.
A procedure is a step-by-step process to complete a task. It is written in the command form (i.e. start the sentence with a verb), providing step-by-step instruction for a task that staff are expected to complete in the same way each time, like a recipe.
A protocol is quite similar but tends to have branching logic and ‘if/then’ statements to navigate anticipated branching points in the task.
Guidelines describe recommended actions for a more variable task that allow for professional judgment – novice staff might be more reliant on a guideline than an expert staff member.
Standards are trying to set a benchmark for a task that users are expected to meet or exceed – any performance below the benchmark would be considered unacceptable.