Fine-art photographers, especially in the digital age, need money to invest in the proper gear to turn their artistic vision into finished artwork.
The conundrum is that digital, by its nature, is not one-of-a-kind.
For example, an etching made of a painting, something commonly done before the invention of photography and color printing processes.
Print editions are shown as a fraction, the bottom number being the total number of prints made and the top number being the individual number of that specific print.
If the print bleeds off the edges of the paper, this is put on the back, or in the print somewhere.
A print is signed by the artist to indicate that it is approved, that it wasn't a trial print to check the plate, but the "real thing".
The edition number is on the left, your signature on the right (plus the year, if you're adding one).
If you're giving the print a title, this goes in the center, often in inverted commas.