excel determine if there are any duplicates in a column code example

Example 1: how to know duplicate in excel in two columns

=INDEX($A$2:$B$14,MATCH("*"&D2&"*",$A$2:$A$14,0),2)

Example 2: check duplicates in excel

CLICK ON REMOVE DUPLICATES ON TOP .
CLICK ON HOME -> THEN SELECT CELLS -> DUCPLICATE REMOVE
THEN CLICK OK