Prerequisits:

To share a passman item with another system user, this user must have created at least 1 vault and have sharing keys in all of their vaults (this keys are created by default, but the key size can be changed on the vault settings).

Sharing is performed with 3 simple steps

1. Find the user and select on the dropdown menu
2. Click the "+" button near the search field
3. Assign permissions and click share

You can also share a password vía link with users external to the system

This is quite self explanatory, maybe this article can be expanded in the future