The teacher uses the application which is called Google meet. The best feature of a web-conferencing app that the teacher used is that he/she can record the lesson so that he/she can upload it for those who aren't able to join the meeting. The teachers can also share their screens to present their PPT. There's a group and private chat features, web conferencing not only allows your students to hear a guest speaker, but interact and ask questions as well.
The problem that the teacher encountered during the synchronous classes was unstable internet connectivity. It really affects both learners and teachers because this is the reason why it is hard for the learners to understand what the teacher said, The internet connection can still be improved, you just have to find the right spot for you to get a stable connection.