How expand/collapse paragrapgh field

Hello ,Use this In built Pattern .

Hello [mention:64f594ee16074333920a8126107ac63c:e9ed411860ed4f2ba0265705b8793d05] 

Please take a look at the more-less link design here

https://docs.appian.com/suite/help/24.1/more-less.html#line-27-78-define-description-column

It is also available in the Design mode of interface

you can achieve this by using left() function, first define the number of characters you want to show in the paragraph field at first e.g. left(text, 40) and add a "More" richtextItem where you can put the dynamic link and change the value of maximum numbers of characters you want to show.