Your code implies the use of a userform. In that case, simply reference the names of the various textboxes, etc. holding the relevant values. For example, instead of:
.Subject = "SUBJECT LINE"
you might have:
.Subject = Me.TextBox1.Value
However, I note you also refer to content controls. If the Subject is in one of them, you might apply the 'Subject' title to the content control and use:
Code:
.Subject = ActiveDocument.SelectContentControlsByTitle("Subject")(1).Range.Text