So the team site has been the gold standard for file sharing since the file share was outlawed by most IT organizations. Microsoft has taken several paths to where these files should go. For a team site, use these guidelines for posting to a team site or SharePoint.
You want team members to recognize the document as being relevant to an ongoing project.
You want to spread ownership and permissions across a wider collection of people. If a document is important to the success of a project, it’s a good idea for there to be people other than yourself who can control what happens on the site.
You want permissions to be granted on a site basis, instead of on individual documents. If people have access to the team site, then they have access to documents stored in the site.
Other project-related documents are already saved to the team site library, and others expect to find it there.
You want to create a check-in workflow that assigns the document to someone else.