1. Select Design > Paragraph Spacing.

  2. Hover the cursor over each option to see a preview, and then select the option you want.

  3. CreatingLineSpacing

    For single spacing, select No Paragraph Space.

Change line spacing for part of your document

  1. Select the paragraphs you want to change.

  2. Select Home > Line and Paragraph Spacing, and choose the spacing you want.

    CreatingLineSpacing2

Source: Microsoft