Can I upload files to a server without using ftp or sftp ?
Just with ssh ?
ssh is a connection method but inherently does not 'do' file transfers. You could run commands like tar and cat via ssh but there are specific utilities that are better suited to file transfers with ssh - have a look at scp and rsync.
All SSH implementations I know do include SFTP, so I don't see why would you not want to use it.
Or for a single file, without preserving metadata: