Hey, Nicole B.
In Law Firms sheet if A2 has the domain from Competitor 1.
In a new column, enter this formula
excel
=IF(COUNTIF('PVB Customers (Law Firms)'!A:C, A2) > 0, "Match", "No Match")Drag down
the formula for other rows.
This checks if the domain in A2 exists in any of the 3 columns (A to C) of the PVB Customers (Law Firms) sheet.