how to add the "add content" to menu drupal
Navigate to 'Add Content" page from admin menu &amp; copy the path after $base_url. 

Example - If it looks like "http://example.com/node/add/product" then copy "node/add/product".

Go to your menu and add one more menu item with the Menu link title of your choice &amp; put this node/add/product in Path over there. All the user will have access to this menu item who ever have permission for adding content of this particular content type.