Whilst I donβt use the free avast Passwords feature, but the free version is somehow restricted, possibly not having the synchronize function.
Also see:
Go to the AvastUI > Settings > Components - scroll down to - the Passwords section and expand it. Now click on the ? (question mark - Help) at the top right of the window and it gives more information.
Passwords is available with all editions of Avast Antivirus, including Avast Free Antivirus. Several basic features are available. For additional features, you can upgrade to the premium version.
It would have been nice if they mentioned the difference there