You can register to vote online at: http://bit.ly/2pyzIGb
If you live in Pima County, the Pima County Recorder's Office will help you find information on:
Click on the State of Arizona Secretary of State website for information on:
Vote411.org - Don't have residency in Arizona? On this site, you can pick the state where you "reside" to see details of registering and voting. You can register and find your local polling place online.
Pima County Public Library's Voting and Elected Officials - this webpage has information on elected officials representing residents of Pima County (about 1/2 way down) and on Kids Voting AZ and Kids Voting USA (about 1/3 of the way down).
Tucson City Clerk's vote-by-mail calendar: http://bit.ly/2sYqJAJ
Pima County Recorder's Office: http://bit.ly/2bj0xsD