i have a doubt

Question

if a user is registered at the website that particular user information i.e user name and password is sent automatically to the user's email...how this process gets done????one more thing i have created a .cs file named registration.cs for inserting user records into database now the thing is where should i write the email script to send that information to the user should i need to continue in the same registration.cs file or should i need to create a separate .cs file to write the email code to get the things done