Thank you, Doug.
I added that piece of code to my macro and it worked like a charm. With just
a slight problem: after the macro is executed, the fields are unprotected and
I can't use the "Clean fields" option in the form toolbar. Is there any way
of reversing the process at the end of the macro?
Something like "Unprotect/Unlink/Send by mail/Link and protect document
again". The purpose is to restore the initial state of the fields/document,
keeping all the protections and fields' definitions.
I had the document protected with a password. I had to remove it, the code
you sent me gave an error "Invalid password". How can I keep the password
protection and only let this macro unprotect the document? Any parameter I
can use? ActiveDocument.Unprotect.Password."my password" or something like
that?...

Here is the current macro I'm using:

Sub sendmail()
With ActiveDocument
  .Unprotect
  .Fields.Unlink
End With
 
 With Application.ActiveDocument.MailEnvelope
   .Introduction = " "
 
          With .Item
           .Subject = "Doc title"
           .To = "mymail@mymailserver"
           .Send
       End With
    End With
End Sub
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