We are pleased to present the proceedings of the IV Workshop on Information, Data, and Technology (WIDaT 2021). We initially planned this event to be held in Belo Horizonte, Brazil, hosted by the Federal Center for Technological Education of Minas Gerais (CEFET-MG). Still, due to the COVID-19 pandemic, we celebrated it virtually from 20-21 October 2021. In its fourth edition, we aimed at bringing together, through interdisciplinary approaches, researchers and other professionals oriented to data access and use coming from computer science, information science, engineering, mathematics, and related fields. The event also focused on promoting the approximation of research groups that work in the data and information field. We tried to discuss several dispersed initiatives, but of great potential for integration among themselves.