User can create WFS servcie based on folder with shapefiles. If user decide to add more shapefiles to the WFS service later on, they can do that by re-indexing the WFS service without recreating the WFS service.
Here are the steps:
 Add more shapefiles to the data folder where user create the WFS service
 From data manager->Services, right-click on the WFS servcie that user want to add more features, choose "Edit provider".
From "Data source" tab, click "Index data" and "Create Types and mappings".
Click OK for overwirte existing files.
 From "Service Info" tab, click "Flush Service Cache" and "Restart service"
 Done. Now refresh data manager, new features will show up in WFS.