I'm looking to transfer a file from my Ubuntu VPS via Crontab to my domain's FTP which is web hosted.
To provide context, there's a file on my VPS which I want to be made available on the internet, and it's constantly updating, so I want to push it from the VPS to the web server automatically.
You'll need to look at creating a script that performs the FTP upload of your file from the VPS to your web server.
Then add a crontab entry to run that script at your required schedule.