Adding new key values in list of dictionary in all rows

Hi, you can use the map function for this. We don't have any direct way of doing that we have to apply loop  to create a custom map and then use it.

https://docs.appian.com/suite/help/22.3/fnc_system_map.html

a!localVariables(
  local!xyz:{
    a!map(id: 1, name: "Jane Doe"),
    a!map(id: 2, name: "John Doe")
  },
  a!forEach(
    items: local!xyz,
    expression: a!map(
      id:fv!item.id,
      name:fv!item.name,
      newKey1:null()
    )
  )
)

You can use a!update(). It is used to update the value of the passed key and if the key doesn't exist, then it will create a new one.