To widen the choice of the default fields in the user database you can add new fields -> Settings - Additional Fields - Add
You can choose the Type of Field from the drop-down menu:
- List: it creates a filed with multiple selection of fixed values from a list.
To create lists, after adding the new field it is necessary to specify all the required values by clicking on the button List Values (next to the name of the field).
If the Visible box is selected, the additional fields will be shown in the user's profile