The process is that you are sending a letter (email) to your senators. You put your name and address in because the letter comes from you, a citizen of the state (based on your address) and a constituent of the senators.
The letter has been prepared for you by the GOA. You are free to edit. I added stuff about the judge not being able to say what a woman is.
You can also just call your Senators directly and talk with their staff. Also written letters via snail mail are worth more points at the offices than emails. Staffers do relay the method of point of contact and those are weighted. Personal visit is highest, then US Mail then phone call then email then emails from special interest groups.