Training institutions send SMS apps in groups.

In many cases, it is best not to send messages in groups to disturb others, because they are usually labeled as harassing short messages, which are of little use and will lose popularity. If you want to promote it, it is suggested that you can distribute leaflets online or organize some people who are willing to do it online. Of course, if you think it is necessary to send a group, I recommend you to use Reed zs. These are all my suggestions, I hope I can help you.