The OrderByUserFieldInput input includes various settings.

Table: OrderByUserFieldInput

userFieldOrderByUserFieldyes The user field by which to sort users. The datatype is an enumerated list of chocies: FULLNAME, USERNAME, or DISPLAYNAME.
orderOrderByDirectionyes Whether to sort users in descending or ascending order. The datatype is an enumerated list: DESC, or ASC.

[a] Some arguments may be required, as indicated in this column. For some fields, this column indicates that a result will always be returned for it.