Backup a remote server with Rsync on macOS or Linux

Rsync is perfect to incrementally backup a remote server on macOS or Linux:

rsync -a user@ "/Volumes/Server Backup/"

rsync The program we’re using
-a archive mode
user The user we’re using to connect to the server.
@ The server we’re connecting to.
:/srv/users/username/apps/sync-this The folder you want to backup.
"/Volumes/Server Backup/" The - local - backup destination.

The reason I’m using the quotation mark for "/Volumes/Server Backup/" is that there’s a space between Server and Backup.