The easiest way is to create a Compose or a string Variable action which contains a carriage return. I usually name mine cCNST/carriageCNST or cVAR/carriageVAR depending on my situation (if others will be interacting with the flow).
If you use it a lot in a flow it is far easier to call the constant/variable, than to type out the alternative.
Technically it's a shorter and easier method than the alternative which is to use the decode URI functions in the expression language on the value '%0D'.
decodeUriComponent('%0D')
or
uriComponentToString('%0D')
