The way to add borders to paragraphs is much like one of the methods to underline text in Word.
First select the content you want to add borders.
Click Home – Borders.
In the pull-down list you can choose different types of borders. Here I choose All Borders as an example.
You can also select Borders and Shading to enable further settings for the style, color, or even shade of borders.
Here’s the result I got. You can also have a try of adding borders to some paragraphs in your own document.