Microsoft Teams helps you manage your documents by providing a Files tab on each channel. Keep critical files visible at all times by pinning them to the top of the Files tab.
The Files tab on a Teams channel gives you a safe place to keep the files you need to have access your team, which are automatically backed up to SharePoint. This makes the Files tab a popular place to store documents, but this convenience costs money: You can no longer find files easily once you have a large number of them in the list.
Fortunately, there is a simple way to keep your most critical documents visible: by pinning them to the top of the Files tab. This will place the documents at the top of the list.
To pin a document, select it by clicking on the circle on the left, then select "Pin to Top" on the toolbar.
You can pin up to three files at the top of the Files list. To pin a file, select the pinned file and click Edit Pin> Unpin.
You can also change the order of the pinned files if you have more than one by selecting the file and clicking Edit Pin> Move Left or Move Right.
Attaching documents to Microsoft Teams is a simple and elegant way to keep the most critical documents visible to your team.
Source of information: howtogeek.com