Sherri wrote:
I concatenated two columns (area code, phone number) and formatted them so
area code looks like (###); however, the 7-digit phone number still appears
as ####### even though I used custom format ###-#### prior to to
concatenating the two columns. Is it possible to add a hyphen so the final
number looks like (###) ###-####?

One easy way is something like:
=TEXT(A1,"(#) ")& TEXT(B1,"###-####")