I noticed there was this black arrow in the ruler for one of my word documents which I see occasionally. This black arrow gives no information when you hover over it with the mouse, but it seems to be giving the document on the left the proper settings for indentation. I was wondering if there was a name for this marker and why it is not present on the right document.
I was wondering if there was a name for this marker?
It is a left tab stop marker (in Word for Mac).
Why it is not present on the right document?
You haven't added a left tab stop.
Set or clear a tab stop
You can set the following types of tab stops:
- A Decimal Tab stop aligns numbers around a decimal point. Independent of the number of digits, the decimal point will be in the same position. (You can align numbers around a decimal character only; you cannot use the decimal tab to align numbers around a different character, such as a hyphen or an ampersand symbol.)
Source Set or clear a tab stop
The arrows are called "Tab Stops".
Read here how to add and use them in Word for Mac (based on the screenshot you attached).