Final answer:
To create a User in Salesforce, it is mandatory to supply a unique username, first and last name, email, and associate the user with a Profile. For Roles, a name and possibly a place in the hierarchy are required. Profiles require a unique name and established permissions.
Step-by-step explanation:
When creating a User, Role, or Profile in Salesforce, certain mandatory fields must be filled out. For a User, this typically includes first and last name, email, username (which is in an email format but doesn't have to be a valid email address), and a unique alias. Additionally, the user's profile, which defines permissions and access levels, must be specified.
For Roles, the mandatory requirement is to give the role a name, although you may also want to set up reporting structures by defining who is higher up in the hierarchy.
Profiles require at least a name, and you need to set the object-level permissions for that profile as well as field-level security.
In summary, while creating Users, Roles, or Profiles, the mandatory fields are mainly concerned with identification and permission settings to ensure the correct level of access and functionality within the Salesforce environment.