(This tutorial is for MS WORD)
To change your document from
single-space to double-space, you need to be able to access the commands.
Go to FORMAT > PARAGRAPH, as shown in
the picture below:

Once you have clicked on PARAGRAPH, the following panel will appear on your page:

Now look for the box named,
LINE SPACING, and click the arrow to be
able to select
SINGLE, 1.5, or DOUBLE spacing.

Your document is now ready for it's new Line Spacing set-up !!!