N99panel panel allows you to upload/manage files/directories via any SFTP compliant client file FileZilla (highly recommended). FileZilla includes many advance features which make most file managers redundant. Now within N99panel, we have implemented ‘Directory Traversal’ under user accounts. From within it, you can do three operations which otherwise maynot be possible in a SFTP File Manager. These operations are – archive generation (making a zip file), archive extraction and recursive removal of folder tree.
Now if you are running a WordPress based website, there are several file manager plugins available like File Manager ( URL : https://wordpress.org/plugins/wp-file-manager/ ) , Advanced File Manager ( URL : https://wordpress.org/plugins/file-manager-advanced/ ) etc.
If you are work on a Linux or a Mac client, you can also do a SFTP mount on to your local file system. You would need to Google it in order to make that work.