What type of variable can you use to store user inputs in Appian?

To store user inputs in Appian, the most appropriate type of variable is process variables. Process variables are specifically designed to hold data during the execution of a process instance, including any inputs from users. They enable the capturing of information provided by users through user interfaces like forms or tasks. This data can then be accessed and manipulated throughout the process flow, ensuring that the inputs are integrated into the application logic effectively.

In contrast, local variables are used within a specific expression or context and do not maintain values beyond that scope, making them unsuitable for persistent user input storage. Expression variables, while useful for storing calculated values or data derived from other variables, also do not persist beyond their immediate evaluation context. CDTs (Complex Data Types) define structures for data but are not variables themselves; they can be used to create process variables but cannot directly store user inputs. Thus, process variables are the most suitable choice for capturing and retaining user interactions within an application.