Function formatPhoneNbr(PhoneNbrStr As String) As String

    Dim tmpNbr As String
    Dim tmpPos As String
    Dim tmpLen As Byte
    Dim i As Byte
    
    ' Get all numbers
    For i = 1 To Len(PhoneNbrStr)
        tmpPos = Mid(PhoneNbrStr, i, 1)
        If IsNumeric(tmpPos) Then
            tmpNbr = tmpNbr & tmpPos
        End If
    Next i
    
    ' Get phone number length
    tmpLen = Len(tmpNbr)
    
    ' Output formatted phone number
    Select Case tmpLen
        Case 7  ' No area code
            formatPhoneNbr = Left(tmpNbr, 3) & "-" & Right(tmpNbr, 4)
            
        Case 10 ' Include area code
            formatPhoneNbr = "(" & Left(tmpNbr, 3) & ") " & _
                             Mid(tmpNbr, 4, 3) & "-" & Right(tmpNbr, 4)
        
        Case Else
            formatPhoneNbr = "Invalid Phone Number"
        
    End Select

End Function

Format Phone Number

Visual Basic