Please provide fields for e-mail use

I am planning on informing my people of this website and I want to tell them how to log in. can you share how I can form the e-mail to include their information i.e. peopleID, churchID, username, password... I want each users to be able to click a link on an e-mail that will allow then to login. so far the only way i can do this is sending individual auto e-mail when I update their profile. I want to send a mass e-mail to all...