It is important to realize that there are two separate processes that you will use to get into your residency - ERAS and the Match.
Electronic Residency Application Service (ERAS®)
The Electronic Residency Application Service transmits residency applications, letters of recommendation, MSPEs, transcripts, and other supporting credentials from applicants and medical schools to fellowship, osteopathic internship, and residency programs using the Internet.
ERAS will direct your personal materials to programs to which you want to apply. This is the first step in getting into a program. If program personnel like your application materials, then you probably will be given an interview opportunity.
The Match Program
Following the interview season, generally October through December, you will post your program rankings to the Match program for processing. More on that in the Match Process page.