Create a channel to focus on a specific topic or project in the Microsoft Teams mobile app. In a channel, you can also hold meetings, have conversations, or work on files together.

Create a channel
1. Go to the team you want and tap More options (...) -- Manage channels -- Add channel (+).
2. Type a name and description.
3. Choose a Privacy level:
Standard - If you create a Standard channel, anyone in the team will see it.
Private - With a Private channel, only people you add will see it.
4. Tap Done.

Post to the channel
1. Tap New post and @mention the channel if you'd like.
2. Add text and tap Send.

Support article: https://support.microsoft.com/en-us/office/create-a-channel-on-the-go-e7a76df3-bfe7-42aa-b016-8f5334e48877