Excel function registration for variable by variable at Stack Overflow https://stackoverflow.com/questions/14731675/is-there-a-way-to-make-udf-that-gives-a-description-like-the-native-excel-functi/21917614#21917614 Attribute VB_Name = "RevitFileNames" Attribute VB_Name = "RevitFileNames" Public Function CleanStr ( strIN As String , Optional ReplaceChar As String = "-" , Optional SpacesToDashes As Boolean = True ) As String Attribute CleanStr.VB_Description = "Remove characters that could interfere with file naming" Attribute CleanStr.VB_ProcData.VB_Invoke_Func = " \n9" Dim I ''generic counter Dim replaceStr As String ''for building replacement string Dim x As String ''character Dim Pass As Boolean ''Pass/fail for character For I = 1 To Len ( strIN ) x = "" : x = ...