You have to run the procedure Sub ExtractMail()
Press Alt+F8 then select ExtractMail then Run... You don't have to type anything in sheet cells...
Just read the lines there and you will find out that this procedure will check all cells from column D
The UDF is not intended for use in sheet, it is for that sub, extract mail...
The function can be used in sheet, but just for one adress, like: =ValidareAdresaEmail("george@yahoo.com"), or: =ValidareAdresaEmail(A1); it will return true if the email is valid, false if not...
For more than one cell, ExtractMail sub will analyze all words in all cells from column D.