An enumerated data type is a data type that groups together a set of values (constant OR fixed) and orders them sequentially from 1 to n.
In the above example, UserType has 3 fixed values and they appear in the same order sequentially in a combobox of a login page.
Instead of using a hardcoded text to select from the combo box, you can use enum. The pre-requisite is to have a fixed set of values that you need in a sequence. The advantages are, in case of change in the order of these constant values OR change in the items itself you don't have to change your code except changing the enum.
In the above example, I can use the enum to verify the order of items in the combobox against enum as well verify the contents themselves.
You can typecast between string & enum, int & enum to use in different requirements. You can also get all the contents of enum using ValuesOfEnum method.