We conducted a cluster randomized controlled trial to evaluate a platform-based training intervention designed to integrate digital technologies into agricultural extension services and aimed to reduce information delivery costs while improving the efficiency of extension systems. The intervention targeted both extension workers and farmers and combined a digital literacy module with modules on digital agribusiness practices. We compared fully online delivery with a blended format combining online and in-person instruction, examining effects on platform adoption, digital literacy, and the use of digital agribusiness practices, as well as the cost-effectiveness of each modality. Both delivery modalities increased knowledge and adoption of the digital platform among extension workers and farmers and reduced digital literacy constraints among farmers, suggesting that digital platforms can facilitate information diffusion in agricultural extension systems. The intervention also increased the integration of digital agribusiness practices by extension workers, with evidence of adoption of some practices among farmers. Both interventions were relatively inexpensive compared to conventional extension training programs.