You can view a microflow as a function that either has no input parameters or does have these.
For example a function that shows a fixed message could be a microflow without input parameters:
ShowMessage() → Calling the function would show a message defined in the microflow, maybe “Hello World”
Now if you add a parameter to a microflow, that takes a string as argument:
ShowMessage(String) → the microflow has access to this string and we could create an activity show message that uses the input parameter. Show if we call the function (microflow) with the argument “Hi Oleksandra” like
ShowMessage(“Hi Oleksandra”) → the result would be a message stating: “Hi Oleksandra”
THis hold true not only for simple strings, integers etc, but also for objects and even for microflows having multiple arguments. So this feature allows to create microflows with more dynamic functions and improves the reusability at the same time.
I hope that this helps you understanding the input parameters a bit more.