There are many different types of chat features in Microsoft Teams. Here are some ideas on how you can make chat work for you.
1. Understanding Group Chats
Outside of open team conversations, you can chat privately and share files and notes with anyone in your organization. Often group chats are created to help speed up the flow of work and get more people engaged in what you are trying to accomplish.
How can I see who is in a Group Chat?
2. Understanding Formatting in Chats
If you wish to start a new line in the chat, you will quickly learn that when hitting Enter, it will go ahead and send your message before you are ready. Try this tip: When you want to start a new paragraph, press Shift+Enter to insert the line break. FYI—If you’ve opened-up all your formatting options, you can press Enter to start a new line of text.
3. Formatting Options in Teams
If you wish to see all of the options available in chat, select Format 
beneath the box where you type your message. In this expanded view, select the text you want to format, then choose an option like B, I, or U to bold, italicize, or underline the text.
There are also options for highlighting, font size, lists, and more. Check out More options 
for additional formatting options, and the buttons below the box for attaching a file or inserting fun stuff like emoji.