A write-in name with no filled oval doesn't get counted — that's the law, and it's the most common mistake. One more thing: in that race, only mark the write-in. If you fill in more ovals than allowed, it's an "overvote" and the whole thing gets thrown out. So write my name, fill my oval, and leave the printed names alone.
Yes — because I filed the paperwork to make it count. Arizona only counts write-in votes for candidates who've officially registered as write-ins. I did. Your county posts the list of official write-in candidates online and at every polling place — my name's on it. Votes for unregistered write-ins (your dog, a sandwich, your favorite fictional senator) don't count. Mine does. Write it in correctly and it's a real, counted vote.
However you vote, it works the same. Most Arizonans vote by mail — ballots go out in October, the return envelope is postage-paid, and you can mail it or drop it at any drop box or voting location. If you vote early or in person, you'll fill in the oval the same way. The write-in line is on every version of the ballot.
Want to confirm any of this yourself? Good — you should.
Check your registration and track your ballot → my.arizona.vote (the Arizona Voter Information Portal, run by the Secretary of State)
See the official write-in list → posted on azsos.gov and your county elections site, and at every voting location
Pima County voters with questions → Pima County Recorder, 520-724-4330
Other AZ-6 counties (Cochise, Graham, Greenlee, Pinal) → call your county recorder, or 1-877-THE-VOTE