This is now possible in the Field Maps configuration app. https://doc.arcgis.com/en/field-maps/android/help/configure-the-map.htm#ESRI_SECTION1_93E449067ECE49...
However, as far as I know, there is still not a way to update feature templates in the "new" map viewer. You must use ArcGIS Pro or MapViewer Classic.
Adding a template to an existing map in Field Maps can be confusing as there are multiple ways to make it look like it should work, but not all actually update into Field Maps.
First how to do it correctly (as of 7/19/2022):
Carefully follow the directions provided in the documentation.
Note, that this only works in Map Viewer Classic and there you have to start editing features, then click Manage at the bottom of the templates list, and create a new template. If a field has a domain, be sure to enter a valid domain value into the text box as there is no validation.
How NOT to do, but make it look like it should work:
In ANY map editor, add a domain to a field, then use unique symbol renderer to define a symbol based on that domain. Interestingly, doing this will show features in the template list from the method above but the results will not make it into field maps.
Hopefully this is cleaned up soon so that it works with the new map viewer and either templates are tied to symbology or there is some notification that changes to symbology do not affect edit templates.
Hi. Thanks for the detailed information. I've just had a look through the options and it still seems there's no way to add a new feature template in ArcGIS Online. The Field Maps designer only updates the map the layer is loaded into, and not all maps containing that layer. It also doesn't seem to allow the creation of a completely new feature template, just duplicates of existing templates with different field defaults (not a new "category" of feature though added to a Domain after the original layer was published). This seems like a major oversight in the feature service management workflow.
And to clarify, whilst I have managed to add a new feature template in Map Viewer Classic, that doesn't flow through to the new Map Viewer either.
That's a great point. The JS API 4.X based online map viewer simply does not use templates. They are used in Pro and in Field Maps, but that configuration is stored in a separate portion of the webmap configuration for the newer map viewer. The inconsistency is confusing. Thank you for digging into this.
That is confusing. As much as I'd like to see it rolled in for consistency, I'd prefer to see a solution in any format (stand-alone?) compared to the current non-solution.
Idea posted here to get this resolved! Include ability to update feature service Feature ... - Esri Community