How can I recover my information if I didn’t save it on my iCloud?

You can sync data to iCloud. You can back up data to iCloud (not the same as sync). You can back up your phone to your computer. If you didn’t do any of these things there is no way to recover any content.

You asked how to back it up... What you want to do is restore the data that's been deleted. Do you have a backup made before the data was deleted?

If not, then there is no place to recover it from.

Is your phone working at the moment? Are you able to enter your passcode and get into your phone right now?

If not, then it's too late to back it up.

See this support article—>How to back up your iPhone, iPad, and iPod touch - Apple Support

Then your data is gone.