View related data in pop-ups in arcgis online when you publish data

[HanhNguyen2]

I have a feature class containing property boundaries and a table containing the names of the owners of that property. Many properties have more than one owner. I must publish this data to ArcGIS Online and show which owners are associated with which property in a pop-up window.
should I set up RELATE or RELATIONSHIP CLASS before publishing? 

Can you help me choose method is most approciate and explain? I confuse 

[MiguelParedes]

Greetings @HanhNguyen2 

I recommend that you check the documentation on Join Features (Map Viewer) and the Join a table to a feature layer tutorial which should guide you on how to accomplish what you need.  Then, for further guidance on the pop-up configuration, please check Configure pop-ups (Map Viewer).

I hope that helps.

[MarkBockenhauer]

You can use a relationshipclass  1 to many and share that as a webmap.

Then in the popup configuration you could use an Arcade Expression to show multiple owners in the popup.  Something like this.

// hydrantowner is the relationship name
var relatedRecords = featuresetbyrelationshipname($feature, "hydrantowner");
// you can order the attributes returned in the related table field. ASC or DESC ascending descending
var orderRecord = orderBy(relatedRecords, "Owner DESC");
var ownerNames = ""

for (var f in orderRecord){
// Owner is the fieldname in the related tabel that I want to display
ownerNames += text(f.Owner) + textformatting.newline   
}
return ownerNames

[EmilyGeo]

Hi @HanhNguyen2, 

If you set up a Relationship Class between the Properties Layer and the Owners table prior to publishing the feature service to ArcGIS Online, then you can configure the pop-up to show the related (owner) records in the Properties layer pop-up. For more information on how to do that, check out our previous blog article, Rolling Out Related Records in Map Viewer.