Suzanne S. Barnhill said:
I'm guessing you have Click and Type enabled (Print Layout view only).
Depending on where your cursor is between the margins, you'll see lines
representing Left, Center, or Right paragraph alignment. If you
double-click in that spot, you'll get a new paragraph with the designated
alignment. You'll also very likely get a forest of empty paragraphs,
spaces, and tab characters between where you clicked and where the
existing text leaves off. If this horrifies you as much as it does me
(though I can see how it would sometimes be useful), you can disable Click
and Type on the Edit tab of Tools | Options.
--
Suzanne S. Barnhill
Microsoft MVP (Word)
Words into Type
Fairhope, Alabama USA