To set a DateTime field to [Today] + 5 days using a SharePoint Designer 2010 Workflow, this is what I did:
- Create a Local Variable (ETA Date) of type Number
- Use a Do Calculation task in the workflow and set:
value: Workflow Context:Date and Time Last Run (As Double)
operation: plus
value: 432000 (number of seconds in 5 days or 60*60*24*5)
Output to: Variable: ETA Date - Finally, set the value of the respective field of the current item to the ETA Date variable