The purpose of this community service program is to instill insight and knowledge about the skills that a teacher must possess in the post-Covid-19 pandemic. This community service was done through a lecture method using PowerPoint presentations, questions and answers and also discussions on a variety of issues that arise in the school. The seminar activities in the context of community service Pematangsiantar's KN-LWF members' principals and teachers, a total of 63 people, were in attendance at this seminar which was located at GKPS Jalan Jenderal Sudirman Pematangsiantar on November 23, 2021. The result of the implementation of this activity is that teachers understand and also get an idea of what they need to be prepared for in gaining 21st century 4C skills through discussion and also question and answer after the presentation was completed. After completing the community research, the researchers summarized that teachers in the world of education must have the 4C 21st Century Learning Skills and have a profound impact on the nation's next generation, enabling them to face and overcome 21st-century life's challenges.