What happens when in Word 2016 when the home ribbon tab is clicked on?

The home tab is opened up.

Explanation:

When using Word 2016 and the home ribbon tab is clicked on, the home tab is opened up. This tab houses the very basic functions of the word document, a lot of which have to be used if even a simple document needs to be typed.

This tab allows you to change the font as well as the font size and color. The page alignment is also set here as well as the text direction. Even headings can be customized here.

There are a lot more functions but the high level point is that the home tab is where the most basic of functions are, as shown in the attachment.