First, your text will difficult to read, but probably ideal for markup.
Second, do your formatting using styles. You may want to create a paragraph style called "DoubleSpace."

The formatting you want is in the paragraph formatting, set in the spacing setting for the space within the paragraph. The spacing between paragraphs is controlled by the space before or space after setting. I would recommend using the space after setting. If in points, one point equals 1/72nd of an inch.

Understanding Styles in Microsoft Word
Basic Concepts of Microsoft Word - from Shauna Kelly

If you need this formatting frequently, you can save your new style to be in all new documents based on the template. You could also save a blank document containing the style as a template and use that template as the base for new documents where you want to use the style.

This advice would be good for Word 2016 back to at least Word 97.