Muhammadiyah University of Tangerang, especially the Informatics Engineering study program as one of the study programs that participates in organizing campus activities in an effort to add insight and knowledge of students beyond the theory gained during lectures. One example of an activity is a seminar. The seminar encountered several obstacles, namely information related to the activities to be held not yet centralized, making recaps of seminar participants which were sometimes invalid, queues during registration, distribution of certificates, and certificate duplication. The Informatics Engineering Study Program requires an activity management system or application and e-certificate verification to facilitate the seminar registration process until the certificate is printed. The seminar application is built based on a website using the PHP programming language and the database uses MySQL. The method used is a data collection method consisting of observation methods, interview methods, and library methods. And using the Waterfall method as a method of system development which is one of the methods contained in the system development methodology called the System Development Life Cycle (SDLC). The results of this study are the applications built can assist in providing information related to seminar activities, printing, and validating activity certificates online, and the applications built are able to verify e-certificates by utilizing QR-Code technology on android devices.