My friends and I also have a chat room where we upload various funny pictures. You can just ask your friends how they open this video format. Of course, if they don't have MacBooks, I think this article will help you: https://mac.eltima.com/mp4-player.html
. There are many good video players that can help with your problem, the main thing is to choose the best one. And the main thing is that it should fit your MacBook in terms of features.