Am currently trying to build a model where you can add an extra location to a delivery route and the model outputs the quickest route between all them all. I have a shapefile that contain 111 locations of customers address across a city. What feature/process do I have to add to the model to enable the user of the model to select individual locations from the shapefile so that it is added to the route.
As commented by @Midavalo you could:
Select the locations first then pass them to the model. Most tools will typically run on a selection set if there is one present.
or alternatively, perhaps investigate using a feature set to request user input of coordinate information.