The following properties are available to all site columns, regardless of the type of information:
Column name – enter a short descriptive name for the column.
Group – you can specify the site column group where the new column will be located. You can choose an existing group from the “Existing group” drop down or you can click on the radio button for “New group” and create your own.
Additional Column Settings:
Add a brief description.
Designate whether this column must contain unique values. By default this is set to No.
Designate whether the column is required. By default this is set to No.
Complete the additional column settings unique to the column type you are creating.
Column Validation allows you to create a formula that must validate to True in order for the user to save the item the column is associated with. This is not valid for all site column types.
Formula allows you to enter a formula that references the column for which it is created.
User Message allows you to provide a helpful message that will be displayed if the formula validates to False.