User-facing documentation should include the following;

1. How to use a program:
    - Purpose: Clearly state the main function of the program.
    - Environment: Specify the necessary hardware and configurations.
    - Domain and Range: Define the input and output parameters.
    - Implemented Functions and Algorithms: Explain the precise workings of the program.
    - Options: Outline available customization or settings.
    - Running Time: Provide information on the program's performance.
    - Accuracy and Checking: Describe the program's reliability and verification methods.
2. How to validate a program: Present a brief demonstration to prove the system's functionality, including:
    - The main use case.
    - An edge case where the system barely functions.
    - An alternative edge case to show the system's capabilities.
3. How to modify a program:
    - Provide instructions on making changes or updates to the program.