You can also make the argument type “raw” (/R) and it will consume the rest of the command line without needing quotes.
(Unless that stops it being the default argument and forces you to state the argument name at the start if the command line. Not sure about that actually, and not at my PC to test what happens.)
If run the command without specifying argument name, the string containing spaces must be enclosed in double quotation. OR, each space separated string will be treated as an argument .
If run the command with specifying argument name(type RAW), args do not need quotes.