I’m looking to add multiple words to a dictionary for a mentalist prop. It is going to take a lifetime to go through transfer/letraset sheets letter by letter. Is there such a product that will allow you to print words onto paper that can then be used as transfers?

I believe you can use a inkjet printer to print on to sheets of clear mylar . Some of these may have a self-adhesive backing , but even if they don't you can use a clear-drying spray adhesive on one side of the printed mylar sheet to stick it to glass, plexiglass, metal , what have you. Here is one such product: https://www.amazon.com/Grafix-2-Inch-11-......00XALNPI

You mentioned a dictionary. is it a real book ? Leather bound or paper covered ? (I'm not sure what materials the mylar will stick to ... ) Do you have a photo of the prop you want to decorate?

I’m not decorating the book. I want to add some words discretely to some blank space inside the dictionary, such that they look like normal text in the book. I can’t say much more as it will tip the method to a trick which is not mine to tip.