Okay so I said I'd explain how to do the mirror image in Microsoft Word, so that transfers can be printed and ironed on...
once you're in Word, go to the Insert tab up top, and go to the far right to the wonky A labeled WordArt.
Drop that menu down and pick something to play around with. There are limited choices, but you'll see that once you pick one, you can change the font, size, color and outline color. Pick something, then type a word or phrase in. Select a cool font, and the size and click ok. It will appear on your page in a blue outlined box. If you right click on that, you can either edit the text without going back, or select Format WordArt all the way at the bottom. This is where you can change the color of the fill in, or outline. If it is one that has two colors shaded together and you want to change the second one but don't see how that works...OR if you want to make it two colors...click on Fill Effects next to the fill in color.
Play around with that for a bit just to see what you can do. Now to Mirror it...
Now click the Page Layout tab back at the top bar. Far right is Rotate. Drop down menu had Flip Horizontal. Click that and it will flip!
For clip art, it was a lot harder, so I recommend going ahead and flipping your clipart with windows photo gallery or Paint, before inserting. Then you don't have to worry about mirroring the picture or art.
It is really fun to play with. Hard to believe that has always been there and I never knew it!! Have fun!