The ACT is an entrance exam used by most colleges and universities to make admissions decisions. It is a multiple-choice, pencil-and-paper test administered by ACT, Inc.
The purpose of the ACT test is to measure a high school student’s readiness for college, and provide colleges with one common data point that can be used to compare all applicants. College admissions officers will review standardized test scores alongside your high school GPA, the classes you took in high school, letters of recommendation from teachers or mentors, extracurricular activities, admissions interviews, and personal essays. How important ACT scores are in the college application process varies from school to school.
Overall, the higher you score on the ACT and/or SAT, the more options for attending and paying for college will be available to you.