Type your message, verse, monogram, etc. in Microsoft Word. You can also use a picture if you choose. In case you are technologically impared like me, I will let you know how I did this. Insert word art and type your message in the word art box. Edit as desired, until it looks just right. Now use the rotate button in the top right corner (it looks like 2 triangles with an arrow) to flip the words vertically. Thats it! Print a tester page on plain paper to make sure it came out right.
Cut out your message as close to the words/picture as possible. Place face down on the bag in the desired location and iron for about a minute.
Let it cool and peel off backing.