It depends on the operating system and where the files are stored.
If you are running Linux you could use a NFS and mount the remote file system where the Filebeat is installed. Just make sure that you configure NFS correctly and according to your requirements, e.g. if you want to use soft or hard mount (hard could hang the server) and Synchronous vs asynchronous, permissions etc but it still requires configuration on both sides.
If you are storing the files on a Windows share I believe it is possible to read the files with a Filebeat but it is probably not supported nor recommended and there are some other additional risks, see thread below.
If you can upload the files to a Database you could use Logstash plugin to query the DB.
In any case you must expose the files somehow to the remote server which most likely require configuration on both ends.
This is my experince with this type of problem.