No add field in table options

[BrianHovis]

What could it mean when in table options the "add field" command is not visible?  The layer is mine added from my ArcGIS desktop and displays fine in AGOL  I also tried the "save layer" option.  I am wondering if it has to do with my privileges, but I am the organization administrator.  Any ideas on this?

I have consulted Work with fields—ArcGIS Online Help | ArcGIS

[RichardFairhurst]

Typically this occurs when the feature class/table is in Editor mode which won't permit the schema to be modified as long as edits are occurring, or the table is open in another session (including viewing it on the same computer in two different sessions of Desktop or in both Catalog and Desktop at the same time) and you cannot get an exclusive lock on the feature class/table.  Not as sure in the Online environment, but I expect the exclusive lock requirement still holds true.  The listed restrictions affecting Add, Delete and Calculate in the online environment include:

• Add, Delete, and Calculate are not available for copies of layers.
• Add, Delete, and Calculate are only available for hosted feature layers or tables. You must be the owner of the hosted feature layer, or an administrator of your organization.

[BrianHovis]

Thank you Richard, I suspect that it is exactly as you suggest.  I thought I had done all I could to make sure it was a hosted feature and that I am recognized as the administrator, but maybe I should check again.  It will probably be some little detail I am ignoring and I will give myself a smack in the forehead.  More to come and I am awaiting a Eureka moment.