winscp.exe site|workspace|folder
winscp.exe [/path/[file]]
winscp.exe [mysession] [/sessionname=]
winscp.exe [mysession] [/newinstance]
winscp.exe [mysession] /edit 
winscp.exe [mysession] /synchronize [local_directory] [remote_directory] [/defaults]
winscp.exe [mysession] /keepuptodate [local_directory] [remote_directory] [/defaults]
winscp.exe [mysession] /refresh [path]
winscp.exe [mysession] /upload file1 file2 file3 ... [/defaults]
winscp.exe [mysession] [/privatekey=] [/hostkey=]
winscp.exe [mysession] [/clientcert=] [/certificate=]
winscp.exe [mysession] [/passive[=on|off]] [/implicit|explicit]
winscp.exe [mysession] [/timeout=]
winscp.exe [mysession] [/rawsettings setting1=value1 setting2=value2 ...]
winscp.exe [/console] [/script=script_file] [/command command1 command2 ...]
           [/parameter // param1 ...]
winscp.exe [/log=  [/loglevel=] [/logsize=[count*]]]
           [/xmllog= [/xmlgroups]]
winscp.exe [/ini=]
winscp.exe [/rawconfig config1=value1 config2=value2 ...]
winscp.exe [/rawtransfersettings setting1=value1 setting2=value2 ...]
winscp.exe /batchsettings  setting1=value1 setting2=value2 ...
winscp.exe /keygen keyfile [/output=output] [/changepassphrase] [/comment=comment]
winscp.exe /update
winscp.exe /help

Source: https://winscp.net/eng/docs/commandline