We examine whether large-scale information interventions can improve college application outcomes in a centralized admissions system. Using nationwide surveys from Chile, we document widespread information frictions and frequent application mistakes, such as omitting attainable preferred programs or failing to include safety options. To address these frictions, we partnered with the Ministry of Education to implement a large-scale field experiment that provided applicants with personalized information on admission probabilities and program characteristics through customized online platforms. The intervention increased the probability that previously unmatched students received an assignment by 44% and improved placement into higher-ranked programs by 20%. Building on these results, the policy was scaled nationwide, reaching all applicants. The scaled-up version, evaluated via an encouragement design, confirmed substantial gains, including higher admission rates for initially unmatched students and persistent enrollment improvements. Our findings show that low-cost, personalized information policies, when integrated into centralized admissions platforms, can substantially reduce application mistakes and improve student outcomes at scale. The results also highlight how leveraging existing market design infrastructure can enable scalable, cost-effective interventions that enhance efficiency and equity in higher education access. [Funding for this report was provided by JPAL and ConsiliumBots.]