You can add users to a TEAM or ENTERPRISE subscription.
Team members can be designated as Admin or else as ordinary ("Basic") users. The person who made the workspace is its "Owner": always an admin, and cannot be removed.
Depending on your subscription, additional credits will be added to your account each month for each user. Credits are shared between all users of the workspace.
To add a user, admins click "Team" in the left menu:
Click on the Team icon
If you have the FREE edition you will be prompted to upgrade. A bar shows your members and open invitations against your plan's limit (for example "3/10"). Click "New user" (greyed out when the limit is reached) and you will see this popup:
Add New User popup
You will be charged an additional amount on your subscription according to its terms: a line above the fields says what this user costs, or that your plan already includes them. Enter the "First name", "Last name" and "Email". The "Admin" box is ticked by default: untick it for an ordinary user. Click "Invite" to send the invite email (when the user adds to your bill, the popup first states the charge and you click "Invite" again).
The person logs in or signs up with that email address; the workspace then shows in their "Select Workspace" list, and opening it makes them a member.
The new user will inherit all the workspace settings. If they are a normal user, they see only the prospects assigned to them (and, in task lists, prospects where they have a task). In Settings / Workspace Setup (as Admin) you can set whether unassigned prospects are visible only to Admins or to all users.
Each user will need to setup their own email integration.
To change or remove a member, click "Team" → "Select user" and pick them. The pencil changes the "Admin" tick (admins have access to every aspect of the workspace); the bin removes them from the workspace, and they lose access to its data straight away.