How do I add special URLs?

You can put more than just a URL in the URL field. You can put telephone numbers and email addresses in too.
To add a telephone number, write the number into the page, highlight it, click the link icon, and in the URL field type tel:(then the number without spaces). For email address use mailto:emailaddress@email.com and if you want to link to a specific page of pdf online then use the URL of the pdf and at the end put in #page=pgn (in place of pgn put in the actual page number of the pdf you want to go to, not the page number on the foot of the page THE actual page).