There are two ways to ask the College Board to send your SAT scores to colleges. SAT score reports can be sent during registration or anytime after from the College Board website.
While you are registering to take the SAT, you can elect to have your scores sent to up to four the colleges without additional fees. This is true each time you take the SAT, so if you take the SAT twice, you could elect to have your scores sent to up to eight schools. Sending scores to more than four schools will cost more money unless you qualify for a fee waiver in which case you may be eligible to send additional scores for free.
You can always return to your account in the My SAT section of the College Board website to have SAT scores sent to colleges you choose, but there are additional fees required to send any score reports after registration (again, fee-waiver students may be eligible to avoid additional fees).
Also, be aware that processing time required by the institutions requesting score reports varies so be sure to contact the schools and be certain your score reports will be received and processed before deadlines.