How does the merchant create user accounts if using standalone SoftPOS or User-Authentication integration?

The merchant logs in using the credentials received in the Welcome email, both in the Nexi POS app and at posweb.nexi.it. From the portal, the merchant can create user accounts for staff and assign desired SoftPOS/MobilePOS TIDs. Staff receive an email with credentials for the app (but not for the web portal).