automatic form information

Actually i didn't know what to put under the title but here goes. When filling in a form on the computer after I insert my first name and hit tab it automatically fills in other information such as e mail, phone etc. I need to change the e mail address ,how?
Thanks,

Open your Address Book application and make any changes to your email address, address, phone number, etc. The forms fill in for Safari and other browsers use the info from Address Book.

Thanks, that was so easy,