ERAS (Electronic Residency Application Service) is the system applicants use to submit residency applications to programs. It is run by the AAMC. IMGs first obtain an ERAS token from ECFMG / Intealth, then register in MyERAS and add their experiences, personal statement, exam scores, letters of recommendation and program choices.
ERAS is separate from the Match. ERAS gets your application to programs; the NRMP Match decides where you are placed. See the ERAS timeline for how the season unfolds, and the NRMP entry for the Match.