What is an Input?
Sometimes you need to prompt the end user to enter what kind of data they want to see when designing a Query. Query authors do that with Inputs. Configuring an Input lets Users specify what data to pull at run time, rather than hard-coding all the values into the Query.

Informer takes the Input value and uses it in the Query's Criteria or Flow Steps. Criteria need to directly reference the Input to use it as an Input value. See Adding Criteria for more.
For Dataset Queries, later refreshes use the same Input value from the last refresh of that Dataset. Changing the Input value a Dataset uses might cause unwanted changes to visual content, since Datasets can back other content. See Change Inputs and Clear Data for how to change a Dataset's Input value.
Ad hoc Queries prompt the User to re-enter Input values every time the Query runs.