When an activist lands on your letter campaign page, they will be asked to enter their information and their address to find targets to write to.
For our built in target lists, we will match activists to elected officials based on the state, congressional district, and state legislative districts they live in, so each activist will be asked to write to one or more of their elected officials, based on whether you've targeted those officials in your letter versions. For custom target lists, we will match the activist to the single closest target on the list. If your custom list only has one member, all activists will be matched to that one target.
To deliver messages to all members of congress and some governors and state legislature members, we use a system that either uses official APIs or fills out the contact forms these elected officials have set up on their websites. If these forms or APIs ask for additional information from the activist (like phone number or captcha), we will show the activist the fields they need to fill out in order to submit their message. All other elected officials, plus all custom targets, are delivered via email. In all cases we pass along the personal information of the activist writing the letter such as email, name, and address, so the target can properly respond.