How to communicate that creating an account is optional to using the site?

I have a site that can mostly be used without creating an account. Accounts are only needed for things such as preserving favorites across devices, which is minor in the context of the site.

I want to provide forms for users to create accounts, but I don't want login and join buttons and forms on site to imply they need to create an account to use the site, giving users the appearance of friction and causing some to bounce off the site.

How can I best convey in my login and join buttons and forms that accounts are not required for using the site?