The setup of the free 2-person organization is here Get Started with Organizations | Bitwarden Help & Support The main differences will be
- Items in your personal premium vaults can have file attachments and TOTP codes and health reports
- Items in your free 2-person collection will not have those capabilities without upgrading to a family organization
- However simple logins, identities, credit cards and secure notes can easily be shared in the free 2-person Organization
Hope that helps