Pivot Field in Field List but Not Source Data
 

Hello, I typically do not use pivot tables and I have inherited one.
There are two fields, Month, and QTR, that are available in the field
list but they are not fields from the source range? I am assuming
there is a way to create a custom field that is a grouping of another,
in this case date, however I cannot seem to find it. I checked the
user formulas and there are none.
Thanks