Count number of files exist on FTP

There are no FTP commands for listing only specific files using a mask.

So you have to retrieve all files from a directory (e.g. using the FTP LIST command), filter the response (remove all lines that does not contain ".zip"), and count the number of remaining lines.

With WinSCP you can use the scripting mode (or pass FTP commands on the command line) and write the output to a log file (see Command-line Options :: WinSCP[^] ). Then process that log file to get the required information.

[EDIT]
The above block about WinSCP has been written because the initial subject was "Count number of files exist on FTP accessed using WINSCP". But the OP has altered the subject.
[/EDIT]