Securing an Impact Factor rating for a journal
The necessary information is available in the Clarivate Analytics website, which is the official body which calculates and publishes impact factors. The info is based on their citation indexes, which were originally developed by Thomson Reuters.

Information on the journal selection process:
http://wokinfo.com/essays/journal-selection-process/

Journal submission form:
http://ip-science.thomsonreuters.com/info/journalsubmission-front/

Other relevant information on impact factors:
http://wokinfo.com/essays/impact-factor/