Hi Everyone,
As Russell previously commented above, labeling is now supported in the Collector-Aurora beta version that is available for testing right now. Currently the beta is only available for iOS, but Android and Windows will be coming as well.
I would recommend to request access to testing the new Aurora beta version of Collector with your labeling by emailing collectorbeta@esri.com. You will also have access to our Early Adopter site where there is a forum that you can share your feedback as well.
Again, please refer to the following blog post - https://community.esri.com/community/gis/applications/collector-for-arcgis/blog/2017/09/06/the-auror...
"Rich symbology and smart mapping capabilities you rely on to effectively represent your spatial information and publish using ArcGIS Pro will look great in Collector. In addition, it will support displaying labels in your map, the top idea you’ve asked for in Collector."
Thanks
-Kevin