Turn editing on, click 'Add an activity or resource' in the desirable section and select 'URL' from the list.

To add a file to your course, you need to add the File resource in Moodle:

To add headings and subheadings to your Moodle course, you should use the Label resource.

A Page resource in Moodle creates a link to a separate Moodle page that displays content. The Text editor allows the page to display many different kinds of content such as plain text, images, audio, video, embedded code or a combination of all these.