In this polygon layer (red) i try to move the label to the outline of the polygon with the Maplex Engine:
I tried to find a way to solve it in the Placement Properties but i didn't succeed.
Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It only takes a minute to sign up.Sign up to join this community
You are using the Standard Labeling Engine which I can tell because your Placement Properties dialog has only two tabs.
If you switch to using the Maplex Labeling Engine then the option you seek should become available to you.
At version 10.3, with which you have tagged this question, Maplex has been part of ArcGIS for Desktop at all license levels since 10.1.
As documented on the Labeling polygons page from the Help:
You can also label the boundaries of polygons, for example, to help the map reader differentiate between two sides of a political border.
To see what Labeling Engine you are using check the Data Frame Properties: