Select Variable window, but you can also type
them directly in the Variable of the 
Assign element in
action flows or in a widget's property.OutSystems Service Studio 4.1 Help
About Variables
About VariablesIn Service Studio a Variable is a writable element in the scope of your screen or of your action flow. It is an element to which you can assign a value.
Possible variables are: screen input parameters, screen and action input parameters and output parameters, execute action output parameters, local variables, Read/Write runtime property elements, session variables and site properties.
Variables are picked from the Select Variable window, but you can also type
them directly in the Variable of the Assign element in
action flows or in a widget's property.
See Also