=MATCH(lookup_value, lookup_array, match_type)

lookup_value – Value you are interested in
lookup_array – Column you want to look for value
match_type – Whether it should be a exact match or approximate match

Match Function

 =MATCH(D2,A2:A7,FALSE)

Looks for D2 in the Lookup Array in A2 to A7

Match with Msg

  =IFERROR(MATCH(D2,A2:A7,FALSE),"Missing")

In case of Error IFERROR is used to make it display as Missing

Match with ISNA

  =ISNA(MATCH(D2,A2:A7,FALSE))

If #N/A then it would be displayed as True

Match with 2 Columns

  =MATCH(D2,A2:A7,FALSE)&MATCH(E2,B2:B7,FALSE)

In the above code, we are checking the two columns for uniqueness by using two match function
and using && Operator to display the value as 11 or #N/A