You can upload PDFs to a group page in Canvas.
In Group Navigation, click the Pages link.
Pages is designed to open to the front page for a group, if there is a front page selected. Click the View All Pages button to select a page from the Pages Index.
Click the title of the page you want to edit.
Click the Edit button.
In the Rich Content Editor, place your cursor where you wish to insert the PDF document.
In the Content Selector, click the Files tab.
Click Upload a new file.
Click the Choose File or Browse... button to browse your local desktop computer for your PDF file.
Click the document you want to upload  and click the Open button .
Click the Files drop-down menu and choose where you would like to store the file.
Click the Upload button to upload your file.
Verify the placement of the linked file. The text will turn blue indicating that the link is downloadable.
Click the Save button.
View the PDF file by clicking on the file name.