When you click New (or CTRL + N) to open a new document in Word, it opens a copy of the default template Normal.dot saved in the Template folder. Word follows the naming convention Document1, Document2, etc. for a new document. The line and paragraph spacing in a new document is according to the Normal template. You can change these parameters though from the Styles gallery.

1. On the Ribbon, under the tab Home, within the group Styles, click the dialog box launcher icon. Word opens the Styles dialog box. See below image.

1. On the Styles dialog box, point to Normal and then click the down arrow button on the right. A drop-down menu appears
2. From the drop-down menu, click Modify. The Modify Styles dialog box appears.
3. From the Modify Style window, click the Format button (at the left bottom corner) and then select Paragraph. The Paragraph dialog box appears.
4. From the Paragraph dialog box, under the section Spacing, select values in the fields Before and After to set spacing before and after a paragraph respectively.
5. For line spacing, select Single from the drop-down list Line Spacing for a single spacing. Select Exactly to specific a value in the field At. See below image