A family of Microsoft word processing software products for creating web, email, and print documents.
What you are describing is the Click and Type function in Word. You can turn it off at File | Options | Advanced. Go to the "Editing options" section and clear the check mark next to "Enable click and type." Click OK.
As you have noticed, when you make use of click and type, blank paragraphs as well as excessive tab characters are added to the document.
A document never needs blank paragraphs, because having them present only means that you duplicate paragraph formatting for no good reason (instead use Spacing Before/After, Line Spacing, etc. to position text).
Therefore, it is best to turn off Click and Type.