Explanation
The Invoke Method activity is used to add items to a list of strings. In this case, the list is declared as "Colors".
The outcome of the Invoke Method activity will be that the list "Colors" will contain an item with the value
"Yellow". This is because the TargetObject property is set to "Colors", which is the list variable, the MethodName property is set to "Add", which is the method of the list class, and the Parameters property is set to "Yellow", which is the value to be added to the list. (UiPath Studio documentation1) References:
1: Invoke Method - UiPath Activities.