A family of Microsoft word processing software products for creating web, email, and print documents.
Is this the cursor you see?
If so, the text is in a table. (This has nothing to do with Mac-to-Windows conversion -- it's a standard feature of Word on most platforms.)
Another clue is that, if you click in the text, the Table Tools tab appears on the ribbon. That tab is visible only when the cursor is in a table. To see the table's cells when its borders are turned off, click the Layout sub-tab under Table Tools and then click the View Gridlines button at the left end of the ribbon.
Then you'll see light dashed lines. The place you're trying to click is on the right-side edge of the cell.
As the arrows on the cursor indicate, you can click there and drag the edge of the column to the left or right, making the table narrower or wider. What you cannot do is insert text there -- you must click in the text inside the cell to do that.