You can control who can join your workspace by enabling or disabling the “Join by Link” feature.
Join by Link Disabled: When disabled, new users can only be added by an explicit email invitation from an admin.
Join by Link Enabled: When enabled, you can share a unique invite link to allow new users to join. You can further restrict access by specifying a list of allowed email domains. Only users with an email address from an allowed domain will be able to join.