Final answer:
The second largest source of voter applications is through a county or government registration office, following the department of motor vehicles as the largest source.
Step-by-step explanation:
The second largest source of voter applications according to the US Census data between 2014 and 2018 is through a county or government registration office. The largest source is a department of motor vehicles.
A variety of factors influence voter registration, including laws that make it easier to register, such as the National Voter Registration Act which mandates states to provide voter registration on government applications, and new methods like online voter registration and automatic registration.