How to create a WordPress theme / template that updates itself? [closed]

You will always need some kind of connection to the remote server for sending the files, but you can have a more automated experience with an FTP program like Cyberduck (open source). It is responsible for sending the files automatically.

For small editions it works fine, but it's always good to remember that this is a practice that should be discouraged for web projects in general, because remote file editing brings a lot of trouble to a project.

Better to use version control and different development environments (topic for another topic).

You can use an online editor, some hosting services offer online editing by CPanel, File Editor.

It can be a dangerous practice if someone has access to your online editor.

With FTP / SFTP despite the delay in communication, but it is more secure.