Is it possible to maintain data across 2 different sites with a Chrome extension?

Hi everyone

For example if I have 2 websites, Site A and Site B and both have forms but I want to copy the information from the form on site A to fill a form on site B, can that be done? or can data/state from a browser extension only be used on that one site only? I know it would be possible to make use of a server but im wondering if they can all be done locally.

Thank you