MacMail Inbox Data Columns

Question from a member:  In using MacMail, I notice that my Inbox windowhas more columns than I had seen before and I really don't want 
them.  How do you select what columns you want?  The new ones include "file size" and two others that I didn't recognize.  So the basic question is how to determine the inbox columns.
MacSTAC Answer: In the Apple Mail program, right click or control click on one of thge column headings - like "From" or "Subject". you can then check on uncheck the columns that show up.