Either way, you get the Styles & Formatting pane on the right, with the Envelope Address style highlighted. If you have Word 2007 or later, press Ctrl+Alt+Shift+S. If you have Word 2003 or earlier, click Format > Styles & Formatting.Click inside the address text of the envelope that was inserted.
Open the Envelopes dialog, enter any text in the address box, and click Add To Document.To restore single spacing in the simplest way: The default line spacing in that is Single, so if yours is triple or some other large spacing, it's been changed somehow. The paragraph and font formatting applied to envelope addresses are determined by the Envelope Address style of the current template (or of the current document, if it's different from that of the template).