Hi @krispag
After your trigger action:
1. Add a Compose action

and add the following formula expression:
concat(
NAME_OF_COLUMN_A,
' ',
NAME_OF_COLUMN_B,
' ',
formatDateTime(YOUR_DATE_COLUMN,'MMddyyyy')
)
2. Add an Update item action. The ID can be pulled from the trigger action.
Click on the field that needs the concatenated string and select the Compose from the Dynamic content list
