On behalf of the Steering Committee, I have the pleasure of welcoming you to the 4th International Conference on Research and Learning of Physics (ICRLP 2021), which will be held online, in Padang, West Sumatra, Indonesia on September 1st – 2nd, 2021. Due to the impact of COVID-19, many communities from around the world are under strict health measures and strict travel restrictions, and participants of the 4th International Conference on Research and Learning of Physics (ICRLP 2021) are also facing the difficulties of travel restrictions. Considering the situation in order to make academic communication on schedule, ICRLP 2021 has been held online using a video conferencing tool.This 4th ICRLP is organized by the Department of Physics, Universitas Negeri Padang. The theme of the conference is "Flexibility and Innovation in Physics and Physics Education Research in a New Normal and Society 5.0 Era". This topic was brought up because research must continue to be conducted and developed even if the Covid-19 pandemic is not over. As a result, one solution to addressing the limitations of this new normal era is the implementation of research that is flexible while still offering novelty or innovation in the field. Furthermore, as the times change, we are expected to be adaptable, and a concept of a human-centered and technology-based society known as the era of society 5.0 has begun to be applied.I would like to express my sincere appreciation to six distinguished experts as our keynote speakers, all the participants, financial sponsors, exhibitors, supporting organizations and all the committee members who has made 4th ICRLP successful. With these strong support, we are sure 4th ICRLP will be beneficial to all the participants. Finally, I would like to thank the members of reviewers for their kind assistance in reviewing the papers.Dr. Riri Jonuarti, M. SiGeneral Chair of ICRLP 2021List of Organizing Committee and Editorial Team are available in this pdf.