How do you space down 'One Line'?
At the top of the editor is a small Plus Icon labeled 'Tips'

If you click on this icon you will find some tips which will help you with this challenge.
Holding the SHIFT + ENTER key will take you down one line
If you use just the ENTER KEY - this will take you down two lines
Behind the scenes
SHIFT + ENTER will enter behind the scenes an HTML <br> tag which means go down one line
ENTER will enter HTML <p> </p> tags which is known as a paragraph space, which will take you down two lines.
MS Word has an Icon to show/Hide Characters
If you enable this and use SHIFT + ENTER you will see a Line Feed Character. If you use Enter you will see a CR + Line Feed character.

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