To fill out your address correctly:
Provide your actual home address (where you physically live) when registering to vote. This is your "voting address", and it will determine your voting jurisdiction. Do not use a mailing address or post office box (P.O. Box). There is a separate section for a mailing address or P.O. Box.
If you have no permanent address you can use an address/location that will accept mail for you (for example, a friend's or relative's home, a church, a food pantry), and register using that address. You must give an address so that your elections office knows where to send the confirmation telling you the location of your polling place. Most jurisdictions also have addresses for people who are homeless to use.
Go to the Election Official Directory, choose your Sate and Region. Either contact your local election offical or go the Local Elections Website for information.