Can I use the same Save to Koofr account in Chrome and Firefox?

Yes, use the same Koofr account in both Chrome and Firefox.

Install the appropriate version for each browser - the Google Chrome extension for Chrome and the Firefox add-on for Firefox and sign into your Koofr account.

Everything you save from either browser will automatically go into the same Save to Koofr folder in your account. You can also use the extension in both browsers at the same time.