Fill in the lettering you wish.  These ruled lines look like the ones we had back in gradeschool but they work the best to represent exactly what you want.  Simply write in the Capital letters in the top boxes and the lower case letters in the bottom.
If you wish your lettering to be all CAPITALS, write them in the upper boxes and just to reduce any confusion, circle the "C" for CAPITALS.

If you wish your lettering to be all lower case, write them in the lower boxes and then circle the "LC" for lower case.

In order to order both upper and lower case lettering, simply write in the appropriate box. Then circle the "B" for both UPPER and lower.