Note: The following is for uploading TO a My Cloud via FTP. Don’t know of any program on the My Cloud other than maybe GoodSync or even Rsync that has the ability to send files the other way, from a My Cloud to another FTP server/device.
Any FTP client software, app should work for uploading files to the My Cloud using FTP. This assumes one has enabled FTP via the My Cloud Dashboard > Settings and if FTP’ing from a remote location, one has enabled port forwarding of the FTP port to their My Cloud within their network router. FileZilla (https://filezilla-project.org/) is one popular free FTP program.
Note that FTP is generally an insecure protocol. One’s FTP user name and password is often/typically sent in the clear and could be intercepted.
There was a way to mod the My Cloud using SSH to install Monsta FTP (https://www.monstaftp.com/) that would create a web based front end for FTP. It was discussed in this thread/post three years ago. Don’t know if it still works though, or if it works on second gen v2.x firmware My Clouds.
