Beside images and videos, you can also add files in your content. As for images, you first need to upload them and use the File Explorer to insert your file as a link in the content.
Insert your file as link
Before anything else, position the cursor in the text where you want to insert the link to the file. Then, in the editor toolbar, click on the Insert document icon 
In the File Explorer select the file you want to insert in the content and click Add selected files . You can also select multiple files to add more than one file link to the content.
The file is then added to your text as link
