How to add a label in the ArcGIS Pro platform.
First make sure the Add Joins to the model. Then open the Contents, right-click on the layer you want to include the labeling, then choose Labeling Properties. This will open the Label Properties.
As long as you have added joins, you will see the WaterGEMS or SewerGEMS element properties. Choose the label you want to add, then click Apply.
If the label doesn't appear, go to Contents again and right-click on the layer name. Choose Label, which should add the label to the drawing
WaterGEMS for ArcGIS Pro and WaterGEMS for ArcMap FAQs
SewerGEMS for ArcGIS Pro and SewergEMS for ArcMap FAQs