Functional specifications are a type of requirements documentation that describes what the system or product should do in terms of functions, features, behaviors, inputs, outputs, etc. Functional specifications can help the business analyst to document the requirements in a way that is clearly understood by the development team and provides enough information to check if the requirement has been met. Functional specifications can also include acceptance criteria, test cases, data models, user interface designs, etc. References: = PMI Professional in Business Analysis (PMI-PBA)Examination Content Outline (2019), page 10; Business Analysis for Practitioners: A Practice Guide (2015), page 39.