Can I insert "carriage return" in a text variable ? If can, how do I d

You can use the char() function to add special characters to strings. Check an ASCII table for the numbers. The one you want is 10. So char(10) is what look for.

both char(10) and char(13) do work, in the the sample code below, the list view will have four lines instead of two lines
= rule!APN_listViewTemplate(
title: rf!building_text & " - " & rf!suite_text,
details: "Leader Name: " & rf!leaderName_text & char(13) & "Current Status: " & rf!status_text,
image: rule!getLocationImage(rf!buildingId_int)
)

Yes. It is working. Thank you.