To add a line feed to a textbox in SSRS is quite simple – in the textbox expression where you want to add the line feed type:
& VbCrLf &
="To add a line feed in SSRS" & VbCrLf & VbCrLf & "Use the VbCrLf function"
‘To add a line feed in SSRS
Use the VbCrLf function’