I am a intern working for a telecommunications company who is looking to migrate arcmap files and migrating them to arcgis online. We are currently trying to figure out how to customize pop ups in arcgis online. I have done some research and it looks like it may involve a combination of html and Arcade, but I do not know how to access the html code for the pop up.
We are also trying to figure out how to simplify the pop up when it has multiple items that need referencing. For example, a pop up that will refer to photos, work orders, etc…
Best Answer
This is bread and butter of ArcGIS online which can be a very intimidating system at first!
Theres many ways to achieve it, but depending on whether your data is hosted on ArcGIS online, or you are publishing to ArcGIS server etc you may or not have access to them all.
Assuming its a ArcOnline "Hosted Feature Layer", click it in ArcGIS online content list to open.
Click the "Visualisation" tab.
On the left where it shows your symbology is a row of icons, hover them until you find the one "Customise Popup"
This allows you to edit the fields displayed, and select an image to show.
Heres a good help file for this: https://doc.arcgis.com/en/arcgis-online/create-maps/configure-pop-ups.htm