Within Teamwork Desk, when creating a help doc article you may wish to include a link to another Help Doc article or an external source.
To do this, click on the link icon as below from the editor bar when creating an article:
When the modal pops up you will see an option to search existing help docs. When you select one the URL for this will be populated in the 'Link' area.
You can enter text into the 'Text' field which will be used in the body of the article as the link rather than full URL.
For more information see: Help Doc article media options