If this is your initial inquiry about CU Boulder please review the information provided by the Office of Admissions. Their website has resouces about requirements and application deadlines. When you are ready to apply as an undergraduate, review the How to Apply information provided by the Office of Admissions. Be sure to request that all SAT/ACT scores, high school and college transcripts be sent to the Admissions Office.
If you interested in applying as a graduate student, review the Graduate Admissions information available on their website.