If you want the User Field to be calculated, select the Is Calculated checkbox.
The Expression field appears below.
You will note that when the Is Calculated checkbox is selected, the following fields are now hidden because the User Field value will be automatically calculated and displayed without user input:
•Required
•Size (for Text)
•Edit Mask & Edit Mask Type (for applicable types)
•List Items (for applicable types)
•Default
Figure 1036: Selecting "Is Calculated" Checkbox
Click the ellipsis to the right of the Expression field to open the Expression Editor.
Figure 1037: Editing Expression
When you are done entering the expression, click OK to return to the Setup User Field edit form.
Back in the Setup User Field edit form, finish adding any other information you need.