Excel determine previous Month and Year from an existing date

I have a date field 7/12/2016 and I need to extract the previous Month Year from this date. What is the best formula?

Needed format of final data Jun-2016

If you need to return it as date, use DATE, YEAR and MONTH function combination.

=DATE(YEAR(DateField), MONTH(DateField)-1, 1)

Then use Custom Number Format: mmm-yyyy
^{Note: DateField should be the cell reference containing your actual date.}