USE FORMULA 

=DATE(YEAR, MONTH, DAY)

CELL NO OF DATE IN EXCEL (e.g. A3)

 

FOR WEEK DAY NAME

=TEXT(A3,"dddd")

IF YOU WRITE d four times, full name of weekday will be shown, e.g. WEDNESDAY

IF YOU WRITE d three time, half name of weekday will be shown. e.g. WED