Problem with directions: Maps told you to turn right instead of left? Here's where you can save future drivers the same hassle. Pick this option and tap Next; Apple will present you with the last three direction searches you made. Tap Next again, and you'll get the Comments field in which you can explain your mishap.
My problem isn't listed: Should your error not be covered under any of the other four options you can always choose this. You'll simply get a Comments field to fill out and send to Apple; it's probably best to make sure you give a detailed accounting of the issue.
It's just business
In addition to fixing issues with Maps's search and direction capabilities, you can also report problems with specific points of interest. To do so, tap on any location, and then tap the blue arrow next to its name; that will bring up the relevant information card. Scroll down to the bottom of the card and tap the Report a Problem button.
You'll be presented with four different options; choose the one most appropriate to the issue you encountered and tap Next.
Information is incorrect: If, say, your local farm is misclassified as an airport, this is probably the best bet. You'll be given a form with name, address, phone, hours, URL, and category--much the same as the "missing location" option from above. Tap on any field and you can put in your own suggestion for what would fix the issue. In this case, changing the category from Other Airports to perhaps Parks might help. Then tap Send.
Pin is at incorrect location: As one of my friends discovered, Maps sometimes gets confused about exactly where things are. Case in point: Massachusetts Ave. stretches from Cambridge, MA across the Charles River to Boston, MA--but though the street name stays the same, the numbering changes. So a particular restaurant that appeared to be on one side of the river was, in fact, on the other. This is exactly what this option is for: As with the missing location issue from above, you'll be asked to place a pin at the point's correct location and hit send. (It's probably handy to use another mapping service to make sure you're dropping the pin in the correct place.)
Place does not exist: You're craving a delicious sandwich, so you follow Maps to the location of a great sandwich shop ... only to find it doesn't exist. This option actually yields two sub-options--"Location has closed" or "Pin is at incorrect location"--along with a Comments field. Pick the first and you'll just enter the details and tap Send; choose the second and you'll get the same drop-the-pin interface as the option above.
Sign up for CIO Asia eNewsletters.