The general objective of the research was to improve vehicular documentary administration in the San Francisco de Asis Association of Huamachuco, Perú through the implementation of a multiplatform web - mobile application. Type of research applied, with a degree of pre-experimental research, in this sense, data collection tools were used, such as the registration forms, which were validated by an expert judgment, and to validate its reliability Aiken's V coefficient was used. To carry out the web application, the Rup Agile methodology was used, whose phases are as follows: Inception or Beginning, Elaboration, Construction and Transition. In addition, the Mobile-D methodology was used for the development of the mobile application, which has the following phases: Exploration, Initiation, Production, Stabilization and Testing of the software. The results achieved after the implementation of a multi-platform web-mobile application were a decrease in the percentage of coactive ballots by 89%, In addition, the association's complaint response time was reduced by 18 minutes, also, there was a 17-minute decrease in the average time for searching for information on overdue documents and a 9-minute decrease in the average time for generating reports on overdue ballots. The present research is divided into introduction, state of the art, objectives, material and methods, methodology for the development of a multiplatform web-mobile application, results, discussion and conclusions. It is concluded that with the implementation of a multi-platform web-mobile application, vehicle document management was significantly improved.