Partner, account owner (aka Administrator) can add colleagues to work in it. The account owner can add and remove users.
For each user, the Partner himself determines the access rights. Read more here.
The user receives an email invitation from the Partner (Administrator). By clicking on the link in the invitation, the user sets a password for his account.
Next, the User logs in to the Partner Account on Intui with his email and password.
The Partner and its users can change the password for their account.