Esri has developed and integrated the suggestion functionality in the World Geocoding Service that’s available in arcgis.com. The capability has been extended to geocode services published with ArcGIS for Server 10.3 for locators created with suggestions enabled. ArcGIS 10.3 or ArcGIS Pro provides the locator styles that support suggestions. If you have an older version of customized locator styles, you can edit the locator styles to add the required properties and grammars for supporting suggestions, particularly for index building and searching for candidates.
You can download the Enabling Suggestions on Custom Locators technical paper to learn how to customize the locator styles to support suggestions.
For your reference, the download also includes the US Address locator style file with the suggestion elements.