There are no per-user fees in Fathom, so you can share access with as many team members and clients as you wish. Only an 'Administrator' user from your organisation is able to invite other people. To do this:
Login to your Fathom account
Select the administration menu (cog icon) from the top right menu
Select "User Management", and then select "Invite a person"
Fill out their details and select a role for the user
Select the companies and consolidated groups this person can access
Click 'Send Invitation'
This person will be sent an email invitation. They can specify their own secure password and access Fathom.
You can setup and invite multiple administrators in a Fathom organisation.
In addition to providing access to companies and groups, you can choose exactly which areas of Fathom a user can access. This is done using the advanced user permissions.