The user component is can be used to easily add a drop-down menu in your form which contains Microsoft Entra/ Active directory users.
When a user is selected from the list, details like there name and email are added to the form response and can be referenced by other components in the form or workflows. By default the list will only show the users within the Team, however this can be reconfigure to show all users in the configuration tab.
Its important to not that for security reasons, if you configure the user component to the "Entire Organisation" this is by default not available to your guests. You can change this in the Active Directory settings.