In both comic and more serious stories, there may be times when your aim is not to make the reader laugh but rather to have your characters laugh. Other than “he laughed,” how do you indicate that?
One choice is onomatopoeia, which is defined as “a word that imitates a natural sound.” For laughter, your choices are pretty much “Ha ha, “Heh heh,” or “tee hee,” all of which have several drawbacks. “Ha ha” has come to be associated with villains in melodramas (“With a mocking ‘Ha ha!’ he tied the lovely girl to the railway tracks”). “Tee hee” sounds like a tittering teenage girl, which is fine if you character is a tittering teenage girl but not otherwise. “Heh heh” leads to pronunciation problems: Is it “hay hay,” “hee hee,” or “huh huh”? None of them simulate laughter very successfully.
Another choice is to use a synonym such as “He chuckled”—or “snickered” or “hooted” or “roared.” These work well, indicating specific kinds of laughter, as long as you don’t overdo it. Add too many laughing verbs and your story will start to sound like a zoo at feeding time.
Finally, you can use phrases like “burst into laughter,” “shook with laughter,” or “was convulsed with laughter.” The danger here is cliché, which all of these are.
Better to stick with “He laughed” and show us what what so funny.