What type of horizontal line is this in Microsoft Word?

This line goes across the page in a Word document and I do not know how to replicate it without copying and pasting. Here is what it looks like:

It acts like as if it is a margin when you hover over it and click and drag it but it cannot be moved past the text above and below it.

Does anyone know what type of line it is and how to create another?

I'm using Microsoft Word for Mac 2016.

Thanks

EDIT: This is what 3 asterisks (***) and Return results in:

EDIT: This is all 6 other 3 character and return options result in:

Solution 1:

Does anyone know what type of line it is and how to create another?

It's a horizontal line.

The "normal" way (to insert one) is to go to the "Borders" button in the "Paragraph" group and choose "Horizontal Line."

You can also use "Auto Format"

On a blank line, type the 3 characters in a row and then Enter. A line appears across the page.

If you need to remove one, simply Backspace or Delete as normal.

Source 4 Creative Ways to Insert Horizontal Lines in Microsoft Word

And how to change once inserted:

Solution 2:

In my opinion this is a Paragraph border, which is applied from Home > Paragraph > Bottom Border. Then you can customize the way you want.

It is a border just like a text box border.

Source: http://answers.microsoft.com/en-us/msoffice/forum/msoffice_word-mso_other/variable-length-horizontal-line/bfec04cc-930f-4b0f-bb05-5d40d5e7074d