In every team, there was always one default channel, named General. This was intended to be the main place where conversations and activity took place. As Teams evolved, Microsoft realized that people used Teams so differently that General didn't always apply. So now you can rename the General channel and give your main channel a more meaningful name making it more intuitive to organize and navigate in Teams.
1. Go to your Team and click on the General channel and hover next to it and click on the ... and select Edit channel.
2. In the window, type in a new name for the channel.
When you create a new team, you will be prompted to give the first channel a name, it won't automatically name it General anymore.