- Information about the software that describes what the product is and how to use it.

- It can be written assets, video or graphical assets

- Can be written for users, developers, qa engineers etc

- Must be kept up to date

- Product Documentation : 

    - How the product functions

- Process Documentation : 

    - How to complete a task

    - Standard Operating Procedures (SOP)

    - instruction to accomplish common or complex tasks

    - Can be in form of flowchart, hierarchical or step by step instruction

- Requirement Documentation : 

    - Done during the planning phase of SDLC

    - Describes expected functionalities of the software system

    - Software requirements specification, System requirements specification and User Acceptance specification

- Design Documentation:

    - Written by architects or developer team

    - Specifies how the software will be built to meet requirements

    - Consists of both conceptual and technical design document

- Technical Documentation

    - Comments in the code

    - Helps readability for other developers

    - May also document ideas or thoughts during implementation

- Quality Assurance Documentation

    - includes the testing team's strategy, progress and metrics

    - Includes test plans, test data, test scenarios, test cases, test strategies, traceability matrices

- User Documentation

    - Intended for end users

    - Explains how to operate the software

    - Also specifies installation process or troubleshooting system

    - Includes FAQs, installation, help guides, user manuals etc