From the City of Boston website:

Each year, the City of Boston is required by state law to conduct a census of all residents 17 years of age or older. This information is necessary to protect your voting rights and to provide better municipal services. Please take a moment to read the following instructions before submitting your information electronically. 

1. This form should be used by individuals 17 years old or older that live in the City of Boston. 
2. You can only submit information for one person at a time. You must repeat the process for additional submissions. 
3. Check all information for accuracy. Certain fields are mandatory to process the information. 
4. This form does not register you to vote. Request a Voter Registration Form Online or by calling 617-635-3767.

Annual Resident Listing Form

To submit your information, you can:

• Complete the online form and submit it electronically. 
• Or download the Annual Resident Listing Form, fill it out completely and mail it back to: Boston Election Department, City of Boston, Room 241, Boston, MA 02201

The form is also available in other languages.

Visit cityofboston.gov for more information.