With a small amount of text, styles would have little impact on processing speed. Using them is still a very good idea.

As for what is open, any application showing up in the task bar is obviously an open process. Most, though, are behind the scenes. Take a look on your own computer using the Task Manager. (Best to not close tasks if you do not know what they are doing, though.)

As for how various objects are created, take a look at your Insert tab. Play around. I do not use Word as a graphics program much. It has powerful tools but is not as easy as using a real drawing program. Most of my graphics editing is done in SnagIt Editor (which is still not a full-blown drawing program).