Desktop publishing is writing documents on a computer.
Suppose you need to provide a well presented document but you don't trust your computer skills, or your spelling or your typing. Then maybe you need someone to do it for you. And it's not expensive.
Suppose you have written the 'Great Australian Novel' on scraps of paper, envelopes, old serviettes and table cloths. Level Heading can put your rough draft into a final well presented publication ready to go to the printer.
Level heading can check your writing before you have it published. Sometimes the writer gets too close to their work and they leave errors in their work. It will be checked with thoroughness and sensitivity.