Add Content and Notes to a Team in Microsoft Teams

You can upload files or folders directly to the Files tab or create a new file in any Team channel.

Upload a file or folder: While in a channel, select Files at the top of the app, select Upload Upload icon, and then choose the file, folder or template to upload.  

Create a new file: While in a channel, select Files at the top of the app, then select New Cross icon at top of the screen. Choose to create a folder, Word document, Excel workbook, PowerPoint presentation, OneNote notebook, Visio drawing or Forms for Excel. You can also create a link to a website or file.