This article explains how a user can upload a file to a SharePoint site.
Uploading Files on SharePoint
1. Direct to the SharePoint site you wish to add a file, and open the SharePoint site library.
2. Once in the library, you should see an 'Upload' button. Then select which type of document you are wanting to upload.
3. Select the desired file and click 'Open'
4. You should now see your new file in your document library.