Copy and paste between two Macs

I need some help, and this is the best place for that.

I have two mac's and sometime back I noticed if I copy a line of text from one, I'm able to paste that line of text to the other mac. I didn't download an app to do this, it was configured somehow within the system itself.

Earlier on today, I wiped and reinstalled the operating system on one of my macs. Reinstall the application that I had, but now the copy and paste function between two max no longer works. I'm at a lost, does anyone know how to reconfigure that setting.

Your help is greatly appreciated.

Thank you.