Is this data ready to be a sync enabled feature service?
To use the sync capability, all the data in the feature service must be from an enterprise geodatabase. Also, you must prepare the data so it can be used offline and, if required, synchronized through the feature service when you have connectivity.
The data you use in a sync-enabled feature service can be either nonversioned with archiving enabled or, if your organization's data or workflows require it, the data can be versioned.
Be aware that you can only enable the sync capability when all the data in the map is configured exactly the same; you cannot have a mix of versioned and nonversioned data.
Prepare data for offline use—Documentation | ArcGIS Enterprise